Allow specifying extra arguments to CMake format

[krypty]

Hello,

The configuration format is described here: https://github.com/cheshirekow/cmake_format#configuration

Please tell if I got any wrong with regards to contributing to this project.

[TheLartians]

Thanks for the PR! I'm a bit unsure about this one, as cmake-format already provides an implicit way to add config files using the file path, which for example is it convenient to specify different configs for different directories:

Otherwise, cmake-format will search the ancestry of each infilepath looking for a configuration file to use. If no configuration file is found it will use sensible defaults.
A automatically detected configuration files may have any name that matches .?cmake-format(.yaml|.json|.py).

But I do see how it can be useful extra arguments to the cmake-format command. How instead we add a more generic option CMAKE_FORMAT_EXTRA_ARGS to allow users to provide arbitrary extra arguments to the CMake format executable?

[krypty]

Sure good idea, I will come back with the more generic proposition you made i.e. CMAKE_FORMAT_EXTRA_ARGS.

[krypty]

OK, I think I got it right. Tell me if that's not the case :) Should we change the PR title?

[TheLartians]

Looks great, thanks for the changes! I've gone ahead and updated the PR title. ;-)