Refactor Long Quote Block in LiveResource

[pehbehbeh]

see https://hexdocs.pm/credo/Credo.Check.Refactor.LongQuoteBlocks.html

• move everything from quote block to top level module in Backpex.LiveResource
• change some internal function to private; see f7f124b
• remove Backpex.LiveResource.schema/0 function; see 709bff8
• fix live updates for non-id primary keys; see dc051d2
• remove obsolete Backpex.LiveResource.can?/4 helper; see 9bdd735 and a474210
• simplify active filters function; see 2aad9ba
• simplify get_filter_options function; see 2a43e79

[pehbehbeh]

@Flo0807 I changed a few internal function with theoretically could be used from the outside. The chance is relatively small... should we add it to the upgrade guide?

[Flo0807]

@Flo0807 I changed a few internal function with theoretically could be used from the outside. The chance is relatively small... should we add it to the upgrade guide?

I'd say yes, but we don't have to explain every change in detail. @pehbehbeh