Refactor the ViewModelFactory to use multibindings

[aitorvs]

Task/Issue URL: https://app.asana.com/0/414730916066338/1199916263225062/f
Tech Design URL:
CC:

Description:
The ViewModelFactory is in charge of creating all the view models for the whole app. Before it had to:

• depend on all the dependencies required by the view models
• have visibility of all the view model types
• classes that needed a view model had to have a reference to the view model factory

By using the plugin pattern in this class we:

• decoupled the view model Factory class from the actual factories that create the view models
• both factories and the view model Factory can now live in different modules if needed without creating circular dependencies

Steps to test this PR:
This PR affects pretty much the whole app as it touches all the view models we've got. To test the PR test the common app screens to see if something is amiss.

1. App compiles
2. install/upgrade the app from this branch
3. use the SERP to perform searches
4. form the SERP, open several tabs
5. add/remove bookmarks
6. add/remove fireproof sites
7. navigate to settings screen
8. use fire button
9. clear app data and go through onboarding UX
10. for all above, verify app works as expected

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Internal references:

Software Engineering Expectations
Technical Design Template

[marcosholgado]

Nice one @aitorvs! Ship 🇮🇹 !