chore: add multirm module to ResourceManager

[carolinaecalderon]

Description

Add a new multirm module and connect this to the master.
Add a new buildrm function to core.go where the rm is initialized.

Test Plan

See attached unit tests. In the future, I plan to write e2e tests too.

Checklist

• Changes have been manually QA'd
• User-facing API changes need the "User-facing API Change" label.
• Release notes should be added as a separate file under docs/release-notes/.
  See Release Note for details.
• Licenses should be included for new code which was copied and/or modified from any external code.

Ticket

RM-14, RM-38

[codecov]

Codecov Report

Attention: Patch coverage is 76.76349% with 56 lines in your changes are missing coverage. Please review.

Project coverage is 47.29%. Comparing base (fa856ab) to head (0d058b4).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8857      +/-   ##
==========================================
+ Coverage   47.22%   47.29%   +0.07%     
==========================================
  Files        1162     1162              
  Lines      175910   176109     +199     
  Branches     2235     2237       +2     
==========================================
+ Hits        83066    83284     +218     
+ Misses      92686    92667      -19     
  Partials      158      158              

Flag	Coverage Δ
backend	42.41% <76.76%> (+0.32%)	⬆️
harness	63.94% <ø> (ø)
web	42.53% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
master/internal/checkpoint_gc.go	68.04% <100.00%> (ø)
master/internal/config/resource_config.go	94.64% <ø> (ø)
master/internal/config/resource_manager_config.go	71.59% <ø> (ø)
master/internal/command/command_job_service.go	0.00% <0.00%> (ø)
master/internal/config/config.go	74.69% <90.32%> (+13.12%)	⬆️
master/internal/experiment_job_service.go	0.00% <0.00%> (ø)
master/internal/core.go	2.18% <0.00%> (-0.06%)	⬇️
master/internal/rm/multirm/multirm.go	86.18% <86.18%> (ø)

... and 4 files with indirect coverage changes