Make usages of `console`, `validator`, and `serializer` components optional

[Blacksmoke16]

framework component should stub out the required types, but make the related ivars nilable for services that leverage these types. Services that entirely depend upon them, like the debug commands, could likely leverage skip_file macro.

The bundle extension, and ext/ directory logic, should ensure those components are installed before wiring up services related to them.

[Blacksmoke16]

Really the only required shards should be dependency-injection and event-dispatcher. The rest could be considered optional. The http component may also be able to replace the common/ aspect of the contracts component which is good because that should have been a sign I was taking the wrong approach.

Will have to see how all this plays out in practice tho.

[Blacksmoke16]

Thought more on this, here is the current plan:

• Only the required components will be installed by default
• https://github.com/athena-framework/skeleton can install extra ones as needed (routing/console mainly)
• https://athenaframework.org/getting_started/ shall be updated to callout the extra modularity, summarize the features installing each component brings, and the system libs each component requires (if any).
  • Should update docs of each component to better highlight system deps it has
  • I still think all the top level guides make sense, but should add some callouts to denote that specific feature requires component x
  • TBD exactly on this but see if each component's landing page should have a callout related to if using it within the framework or not as a place to document its integration points or something there
  • The getting started page would also be a good place to possibly have a section regarding the available aliases for each component. Essentially covering Document import macro #629
  • The root site landing page also might be due for a refresh