chore: clean up rm module [RM-202]

[carolinaecalderon]

Ticket

Description

Remove rmtest module (it’s empty), and refactor message.goto get rid of actor system messages/replace with the variables themselves

Test Plan

N/A

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.

[netlify]

✅ Deploy Preview for determined-ui canceled.

Name	Link
🔨 Latest commit	96d8932
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/66269a2bef3c510008bea5bf

[stoksc]

lgtm as long as ci passes

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 40.88%. Comparing base (1b212ae) to head (96d8932).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9191      +/-   ##
==========================================
- Coverage   44.72%   40.88%   -3.84%     
==========================================
  Files        1266     1238      -28     
  Lines      154770   152987    -1783     
  Branches     2438     2439       +1     
==========================================
- Hits        69225    62554    -6671     
- Misses      85313    90201    +4888     
  Partials      232      232              

Flag	Coverage Δ
backend	41.57% <0.00%> (+<0.01%)	⬆️
harness	49.48% <ø> (-14.66%)	⬇️
web	35.38% <ø> (ø)

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

Files	Coverage Δ
master/internal/rm/kubernetesrm/resource_pool.go	17.89% <0.00%> (+0.08%)	⬆️
master/internal/rm/kubernetesrm/pods.go	21.23% <0.00%> (ø)

... and 168 files with indirect coverage changes