Initial version of pre-commit hooks

[krish2718]

This has standard checks that are used in BW org across repositories.

[bwt-sloanj]

Since this is being adapted from the internal check_commit.py it is worth bearing in mind that this hook is currently only implementing the checkpatch part of that script - the python function check_commit_message() isn't part of it (probably something I cut out). It therefore needs to be considered if this hook needs to be expanded to also do those checks, or if another hook could do those, or if they aren't wanted for this.

Also, I appreciate that in reviewing this that I am in effect requesting changes to code that you didn't write yourself, and in some cases that I wrote, but what I gave you wasn't complete and we have also migrated Python versions since then.

[krish2718]

It therefore needs to be considered if this hook needs to be expanded to also do those checks, or if another hook could do those, or if they aren't wanted for this.

Well, the per-commit checks are too specific to BWT, so, IMHO, we should drop that for now, and as a first cut stick with checkpatch + spellchecks (codespell). And also, we can just use gitlint instead of custom checking, that can be another hook in this repo added later.