postprocessors

[b1ek]

this removes code from #128 and closes #377, #149, #107, #95

the implementation is no different than the one from #128, but it also can be defined as a serializeable schema in case we want to make some sort of a config file for those.

closes #476, #377, #149, #107, #95

[Mte90]

Can you add a line in the Readme about the bash dependency checker? There is already one about shfmt.

[Mte90]

I want to report that clippy is warning about some function unused.

[Ph0enixKM]

I'll approve once @hdwalters confirms that these changes work on Windows GitBash too

[b1ek]

@hdwalters do the review thing again

[b1ek]

@Ph0enixKM do review!!!!! we're waiting for u

[hdwalters]

@Ph0enixKM do review!!!!! we're waiting for u

He did say "I'll be unavailable for checking PRs starting from today [30/10] until 3/11 too"

[hdwalters]

I'll approve once @hdwalters confirms that these changes work on Windows GitBash too

For some reason, GitHub is not giving me the option to clone this branch using Git; it only suggests gh pr checkout 383. And unfortunately my employer has us so locked down that I can't install the GitHub CLI tool (this is one of the downsides of working for a fintech company).

However, since @b1ek has now rewritten this code, and removed the cfg!(unix) test, I suggest that we just merge it, and fix any problems caused on Windows if they crop up.