Reduce spread of `[GeneralWebHook]` support, stop adding global filters

[dougbu]

• 258

• centralize and minimize metadata lookups, especially per-request lookups
• add abstract WebHookMetadataProvider and implementation (DefaultWebHookMetadataProvider)
• add core constraints and filters to actions from IApplicationModelProvider implementations, not globally
  • constraints and filters use WebHookMetadataProvider in [GeneralWebHook] scenarios
• add receiver-specific filters to actions from WebHookActionModelFilterProvider or WebHookFilterProvider
  • pattern is somewhat simpler than that for core filters; these filters need to check their own applicability
  • add WebHookFilterProvider, an IFilterProvider implementation
  • add IWebHookFilterMetadata to ease registration of receiver-specific filters
• implement IOrderedFilter in all filters
• consolidate and rename lots of classes
  • give IApplicationModelProvider implementations clearer, more specific names

nits:

• make doc comments more consistent
• correct a few oddly-named fields and variables

[dougbu]

:up::date:

• rebased on dev
• no longer in design

[dougbu]

I still think that what's going on here with ActionDescriptor.Properties is much much more trouble than it's worth, but I also don't think it's a priority to change

Agree this approach has downsides and that reworking these details shouldn't be a priority. Deciding on then changing to another approach (e.g. merging the IApplicationModelProviders into one and passing context around) would take time better spent elsewhere.

[dougbu]

c9ab0b4ede