Revert "latest & favorite media entries & collections in dashboard"

This reverts commit a19207e349b3e04fd6d517e22f2b2c70b3e665b0.
Cleanup and reorganize `/doc`: database oriented stuff
rubocop & linted source
migrate favorite filter sets too
Link to tests and coverage results from README
Update database schema/entities diagram, update README point to docs

Squashed commit of the following:

commit 6247fae507b5e455c00e2eb510eb0b9fa1d7d723
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Dec 15 09:22:11 2014 +0100

    ...

commit a116a44265783b83c6e00fed6756c9f1b7ef3fb5
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Dec 15 09:21:10 2014 +0100

    ...

commit 4d544cc4d2a2b6bd0f4f3fb2bdce63c7204ca946
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Dec 15 09:18:26 2014 +0100

    ...

commit bc9c183b5a3d809addb8ae6ea9fda3a9856d99c2
Author: Thomas Schank <DrTom@schank.ch>
Date:   Mon Dec 15 09:06:11 2014 +0100

    Update database schema / entities diagram
favorite filter sets
Merge branch 'madek-v3' into mk_madek-v3_dashboard_resources

Conflicts:
	app/controllers/my_controller.rb
	app/models/filter_set.rb
	app/models/user.rb
	app/views/my/dashboard.html.haml
	spec/controllers/my_controller_spec.rb
fix spec after merge