add include_hidden option to collection_check_boxes helper
Ensure LookupContext in Digestor selects correct variant

Related to: #14242 #14243 14293

Variants passed to LookupContext#find() seem to be ignored, so
I've used the setter instead: `finder.variants = [ variant ]`.

I've also added some more test cases for variants. Hopefully this
time passing tests will mean it actually works.
Don't pass variant in params, it's ignored

We're setting variant above, in request object directly
Don't create addition vars, use options[] directly
Add variants to Template class
Don't pass hash as keys to #find method
Disable LookupContext's cache when looking for template
Rename _setup_options to _options_for_digest
Set format in finder
Add mocked disable_cache for FixtureFinder
Introduce #with_formats_and_variants to prevent problems with mutating finder object
Allow custom JDBC urls

mitigates #14323
better test error messages
Merge pull request #14329 from pch/digestor-lookup-fix

Ensure LookupContext in Digestor selects correct variant
Add Public Api for register new extensions for Rake Notes
Fix the resolver cache and stop mutating the lookup_context

Before we had a bug in the resolver cache so the disable_cache were not
working when passing options to find
Merge pull request #14373 from schneems/schneems/jdbc-ar-2

Allow custom JDBC urls
Fix #to_json for BasicObject Enumerables
Merge pull request #10278 from codeodor/fix-to_json-for-Enumerable

Fix #to_json for BasicObject Enumerables
Remove .scss, .sass, .less, .haml, .slim, coffee from Rake Notes. Now we have an API for register it in the corresponding gems