MM-35518 - Add CodeQL check

[srkgupta]

Summary

Added step to run automated CodeQL checks. Once this file is merged, the codeql checks (code scanning checks) will automatically be performed on following conditions:

• new pull requests to master branch
• scheduled to run every week once (it automatically pulls the latest codeql checks added, if any)

Ticket Link

Fixes https://mattermost.atlassian.net/browse/MM-35518

[codecov]

Codecov Report

Merging #77 (d8d4c73) into master (cc1317a) will decrease coverage by 0.63%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master      #77      +/-   ##
==========================================
- Coverage   26.03%   25.39%   -0.64%     
==========================================
  Files           7        7              
  Lines         315      315              
==========================================
- Hits           82       80       -2     
- Misses        216      217       +1     
- Partials       17       18       +1     

Impacted Files	Coverage Δ
server/utils.go	87.87% <0.00%> (-6.07%)	⬇️

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