Enable `readability-identifier-length` lint check?

[HalosGhost]

As mentioned in #162, much of the codebase is not compliant with this newly-added clang-tidy check. Looks like the default settings (which we mostly tend to keep) requires that variables names be 3 characters long or longer.

This is as much a question on whether or not we should enable such a stringent check as it is a question of what settings we should enforce.

[HalosGhost]

cc @metalicjames

[SumantxD]

@HalosGhost could you assign me this issue, i would like to work on it

[HalosGhost]

Before you start working on making the code compliant with the check, do you have any thoughts on whether or not the default length is appropriate, or do you think it makes sense to just fit with the default?