Simplify reading query and annotations

There was some code complexity here aimed at ensuring that _either_
config.annotations or config.query would be set but never both. It isn't
really necessary for the code to maintain this condition, especially
given that the way that both settings are read from the URL fragment
means that both cannot be present at once anyway.

Extract a new configFuncSettingsFrom() function

Extract app() into separate function

Simplify a test fake

Extract some code for reading config settings from a
window.hypothesisConfig() function out of
annotator.config.config#configFrom() and into a new, separate function
annotator.config.settings#configFuncSettingsFrom().

This function can now be unit-tested separately and the long
configFrom() function gets a bit shorter.

Extract the code for reading the config.app setting into a separate
function.

This function can now be unit tested separately, and the long
configFrom() function gets a little shorter.

Search by DOI: Include DOI URIs in search URI list

When the `search_for_doi` feature flag is enabled, include `doi:` URIs
in the query to the `/annotations/search` endpoint.

This enables the client to fetch annotations made on different URLs
which are associated with the same DOI as the current page.

adding console log capture to karma

Search by DOI: Add document metadata to app state

Move config.js and extract-annotation-query.js into new config dir

Fix ghost adder

The adder is not off screen, it's in the top-left corner.

Hide the `<hypothesis-adder-toolbar>` element, rather than its
containing `<hypothesis-adder>` element, when hiding/showing the adder.

Since 56f5243e hiding the parent
`<hypothesis-adder>` element doesn't work because, to protect them from
third-party CSS elsewhere in the DOM, its child elements no longer
inherit its CSS properties.

Fixes https://github.com/hypothesis/client/issues/414

Adder() contains a `var self = this` line and a line that assigns the
`element` that `createAdderDOM()` returns to `this.element`, but it
usually accesses `element` via the local variable element (and
occassionally as `this.element`).

Change this to be consistent: assign `self.element = createAdderDOM()`;
always access it as `self.element` not `this.element`; delete the local
variable `element`.

This just makes the code a little simpler and more self-consistent.

Move the extraction of search URIs from frame metadata out of the
callback for the "getDocumentInfo" cross-frame request and into a
selector function.

This will make it easier to change the set of search URIs that the
client sends for a given set of connected frames depending on enabled
features. It also makes it easier to implement tests for this.

 * Remove `searchUris` from frame objects in the app state and instead
   compute this list on-demand from the frame URI and metadata when
   needed.

In preparation for conditionally including 'doi:' URIs in the set of
search URIs depending on the active feature flags, store the complete
document metadata for connected frames in the app state, instead of just
extracting the document fingerprint and search URIs.

This will allow the code that searches for annotations to later extract
the set of search URIs just before it sends the query, at a point when
the client has feature flag information.

In particular add a test for the `documentFingerprint` property in
preparation for changing the structure of frames objects in the app
state.

extract-annotation-query.js is purely about reading a couple of config
settings and is only used by config/config.js, so move it from the util/
dir into a new config/settings.js file.

config/settings.js is going to become a file containing all of the
different functions for reading different config settings. These
functions are imported and used by config/settings.js. For a start, move
extract-annotation-query.js's two functions into settings.js, but later
we'll be adding more functions to this file.

These functions are in a separate settings.js file, rather than just in
the config.js file that uses them, so that they can be unit tested
separately.

Add a src/annotator/config/ directory to contain all config-related code
for the src/annotator/ part of the code. Move config.js into the
directory.  We're going to be adding more config-related files in this
directory later.

Ignore all config other than direct linked ID  from host page.

configuration on the host page other than the query and annotations.

Fixes https://github.com/hypothesis/product-backlog/issues/209

Adding group leave, switch, and view activity metrics

Split extract annotation query into two separate functions

For a future refactoring of this config code I need to have one function
per config setting (the function returns the value of the config
setting).

extractAnnotationQuery() is actually a single function for two config
settings - it returns either {query: *} or {annotations: *} depending on
what's in the URL #fragment.

This doesn't fit into my planned refactoring, so split
extractAnnotationQuery() into two settings functions: one for
config.query and one for config.annotations.

Refactor extract annotation query

Only match the `#annotations:<ID>` regex against the URL if the
`#annotation:<q|query>:<QUERY>` regex, which takes precedence, doesn't
find a match.

This also makes it clearer that the URL-safe base64 IDs comment applies
to `annotFragmentMatch` only not to `queryFragmentMatch`.

I think this makes the code more readable.