enhancement: CSharpier config filename and path override ability

[TommyE123]

Fixes #3553

CSharpier - Filename and path override improvements

This change adds the ability to override the location of the .csharpierrc filename and path. Currently its using the default option for the command -c which is incorrect and requires --config-path csharpier documentation.
This also now allows the .csharpierrc file to be placed in the default linter path which currently doesn't work due to the wrong command parameter.

Please note this doesn't allow an .editorconfig to work in another location as this isnt currently supported by csharpier. (see issue 3553 for more info) However if this changes then the fix should also work nicely with this approach as well.

Proposed Changes

1. Fixed config path option command.
2. Added default file name .csharpierrc.
3. Updated schema to reflext the 2 new available options avaiable. (assumed this was required but please say if this isn't or I need to update anything else?)

Testing - Mixture of CI builds to demonstrate the fix

GITLAB - Both filename and location overridden:

GITLAB - .csharpierrc in default Linter rules location:

AZURE - Filename overridden .csharpierrc.yml in default Linter rules location:

GITHUB - Filename .csharpierrc.yml in root (no extra megalinter parameters set):

[echoix]

Again as always, you went above and beyond to prove the work and the justifications. (I don't even have access to a setup that has these three CI platforms). The actual contents of the PR look correct.

Rerunning the failed test for unrelated reasons, and setting up the automerge like the other PR.