Drop need to declare spec feature files

[dapplion]

Part of effort to reduce boilerplate steps when adding new spec features

Auto-include all files in spec feature directory. Then expect contributor to declare special include / exclude cases only if required

• Related to Refactor setup.py #3393

[hwwhww]

I like it 👍 ! It solves the pain of adding file paths one by one and sometimes missing some files. Thank you a lot @dapplion!

[hwwhww]

There might be multiple extra spec files of one fork. Maybe use <FORKNAME>: List[Path].

[dapplion]

Used a string since the file accumulator below is not a List. If there are multiple just do a multiline like in

consensus-specs/setup.py

Lines 1072 to 1078 in efd2429

	self.md_doc_paths = """
	specs/phase0/beacon-chain.md
	specs/phase0/fork-choice.md
	specs/phase0/validator.md
	specs/phase0/weak-subjectivity.md
	specs/phase0/p2p-interface.md
	"""

[hwwhww]

I was thinking about changing how we append EXTRA_SPEC_FILES[fork] together. But it's fine now; we can figure it out when we have multiple extra spec files of one fork.