Renamed RPacketCollection Class to RPacketTracker

[DhruvSondhi]

This PR aims to rename RPacketCollection to RPacketTracker Class.
Multiple variable names has also been changed to reflect this renaming.

In continuation of PR #1776.

How has this been tested?

• Testing pipeline.
• Other.

Type of change

• Bug fix.
• New feature.
• Breaking change.
• None of the above. -- Renaming of existing feature

Checklist

• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
  • (optional) I have built the documentation on my fork following the instructions.
• I have assigned and requested two reviewers for this pull request.

[tardis-bot]

Before a pull request is accepted, it must meet the following criteria:

• Is the necessary information provided?
• Is this a duplicate PR?
  • If a new PR is clearly a duplicate, ask how this PR is different from the original PR?
  • If this PR is about to be merged, close the original PR with a link to this new PR that solved the issue.
• Does it pass existing tests and are new tests provided if required?
  • The test coverage should not decrease, and for new features should be close to 100%.
• Is the code tidy?
  • No unnecessary print lines or code comments.

[wkerzendorf]

The test fail?

[codecov]

Codecov Report

Merging #1861 (553141e) into master (6649e68) will not change coverage.
The diff coverage is n/a.

❗ Current head 553141e differs from pull request most recent head c8a151d. Consider uploading reports for the commit c8a151d to get more accurate results

@@           Coverage Diff           @@
##           master    #1861   +/-   ##
=======================================
  Coverage   62.12%   62.12%           
=======================================
  Files          66       66           
  Lines        6809     6809           
=======================================
  Hits         4230     4230           
  Misses       2579     2579           

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[andrewfullard]

Address Wolfgang's suggestion and it's good to go.