feat: Custom logger added with option to attach handler

[anees17861]

Added a static class MeshLogger.
This class accepts a LogHandler object providable by app.
If the LogHandler is null then it falls back to android.util.Log print statement.

closes #521

[CLAassistant]

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[anees17861]

Hi @roshanrajaratnam,

Any update on reviewing this?
I understand that the number of files to review is huge but just to make your life easier, I'll provide the summary of actions that I did:

Created MeshLogger file

Find and replaced all instances within the mesh module of the following
import android.util.Log; with import no.nordicsemi.android.mesh.logger.MeshLogger;
Log.v with MeshLogger.verbose
Log.d with MeshLogger.debug
Log.i with MeshLogger.info
Log.w with MeshLogger.warn
Log.e with MeshLogger.error

The only issue is if some other feature gets added with logs before this PR is merged, then the PR will need to be updated to accommodate those changes. I have unfortunately not found a way around this

[roshanrajaratnam]

Hi, thanks for your contribution and we really appreciate it. I have been a bit busy with some other stuff, I will get this merged today :)