remove `-f ast` from compiler outputs

[cyberthirst]

Version Information

• vyper Version (output of vyper --version): 533682df9895dabab3033df776953c595ea0107c

What's your issue about?

• remove -f ast option and decrease the compiler's surface
• in most cases the annotated ast is the preferred option

---

• leaving this open for discussion in case someone might have a usecase for ast without annotations (e.g. error recovery)
• as per the referenced version, the output doesn't even contain imports making it even less useful

[cyberthirst]

further, the following deepcopy: https://github.com/vyperlang/vyper/blob/533682df9895dabab3033df776953c595ea0107c/vyper/compiler/phases.py#L166

should be most likely run after the imports are resolved.

if the imports were added to the ast output, the output might be incorrect as the imports would not get deepcopied and thus could be annotated if we requested (in this specific order) -f annotated_ast, ast

[charles-cooper]

we could raise a DeprecationWarning for a few releases and see if anybody complains

[trocher]

It's really useful for tooling that want to parse Vyper code that might not be compiling (e.g. Language servers) https://github.com/trocher/couleuvre