Tweak completions for bash and zsh

[cole-h]

I use fish currently, so I manually tweaked those completions to allow for things like tab-completion of GPG keys, entries, and directories in the store. I don't have the time right now (or even the desire, really) to do this for shells I don't use, so contributions welcome!

A good reference would be pass's own completions, located in this folder: https://git.zx2c4.com/password-store/tree/src/completion.