add `type-coercion.js` util with 4 methods. These are used on incoming the host-config values `openSidebar` and `requestConfigFromFrame` which may have an incompatible type upstream (via3) from what the client expects.

- toInteger
- toObject
- toString
- toBoolean

These methods coerces specific values into types so that downstream (client) methods can make assumptions. This is part of the prep work to support via3 which will eventually only export strings values in the config.