refactor: add VULNERABLE_SOLC_VERSIONS and logic

[devtooligan]

addresses #1476
precursor to #1424

[0xalpharush]

I think this approach makes sense. There's probably other areas it could be used e.g. the external function detector.

[devtooligan]

@0xalpharush fixed and ready for re-review.

question: do you prefer 1 commit per pr? so github commit --amend and github push --force-with-lease for additional changes? or do you prefer to keep all the interim history commits? i assumed the former.

[0xalpharush]

@devtooligan There's not a strict style atm. I think force pushing is fine for small commits but if you make large changes and the commits aid in reviewing the PR, leaving the interim history makes sense.

[montyly]

I would recommend against force push, or changing anything that was pushed on github (see Linus's point of view on rebasing)

Github allows to squash commit when we merge the PR, so it's ok to have multiple commits in the PRs ;)

[montyly]

This is a great idea, I think we can clean up a lot of detectors following this schema. Thanks @devtooligan

[montyly]

Note: when merging the PR, we need to update https://github.com/crytic/slither/wiki/Adding-a-new-detector

[devtooligan]

@montyly wrote:

Note: when merging the PR, we need to update https://github.com/crytic/slither/wiki/Adding-a-new-detector

@0xalpharush maybe you or someone else can help with this. Github wiki is not set up very well for open source contributions from outsiders 😄

We will need to update the snippet in the wiki with:

VULNERABLE_SOLC_VERSIONS: List[str] = []

Then down below in the notes maybe add something like:

`VULNERABLE_SOLC_VERSIONS` lets you specify which versions of solc
are vulnerable.  If this list is not empty, the detector will
only run if the solc version is included on the list.

[devtooligan]

@0xalpharush @montyly Requested changes made. Aside from updating the wiki, this should be good for final re-review and merge.

[montyly]

I merged the PR through #1485. Thanks again @devtooligan, this was a great idea