[ENH]: Add functions to mrtrix3 interface

[lbutry]

This PR updates the mrtrix3 interface in nipype and closes issue #3612

List of proposed changes:

1. Added "MaskFilter" for dilate/erode filteres
2. Added "MTnormalise"
3. Added "Generate5tt2gmwmi"

[teanijarv]

What's the status on this PR? I just found as well that mtnormalise doesn't have interface in nipype.

[effigies]

Apologies for the delay. Please review the change I made (apart from the merge fixing up Zenodo author ordering) and the CI complaints.

Once the tests are passing and you're okay with this, we can merge.

[codecov]

Codecov Report

Attention: Patch coverage is 78.43137% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 63.16%. Comparing base (f1a8909) to head (27d285a).
Report is 11 commits behind head on master.

❗ Current head 27d285a differs from pull request most recent head 5599348. Consider uploading reports for the commit 5599348 to get more accurate results

Files	Patch %	Lines
nipype/interfaces/mrtrix3/utils.py	78.43%	11 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3613      +/-   ##
==========================================
+ Coverage   63.14%   63.16%   +0.01%     
==========================================
  Files         308      308              
  Lines       40824    40875      +51     
  Branches     5655     5655              
==========================================
+ Hits        25780    25820      +40     
- Misses      14031    14042      +11     
  Partials     1013     1013              

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[lbutry]

Thank you for reviewing! The changes you made are all good in my opinion.

Unfortunately, I'm rather new to GitHub and not familiar with the CI complaints. I won't be able to fix them. I would appreciate it very much if someone could help me out here.