Add Internal GitLab CI config

[kevalmorabia97]

• Add ability to run more extensive tests nightly in internal gitlab ci with multi-gpu runners
• Also allow internal developers to trigger these tests on their GitHub PR on-demand

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 73.68%. Comparing base (73d2610) to head (0d8538a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #251   +/-   ##
=======================================
  Coverage   73.67%   73.68%           
=======================================
  Files         175      175           
  Lines       17026    17026           
=======================================
+ Hits        12544    12545    +1     
+ Misses       4482     4481    -1     

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