Rename One Color Per Layer to Monochromatic

[pllim]

Description

This pull request is to rename One Color Per Layer to Monochromatic for image viewers. This is built upon #1343.

Checklist for package maintainer(s)

This checklist is meant to remind the package maintainer(s) who will review this pull request of some common things to look for. This list is not exhaustive.

• Are two approvals required? Branch protection rule does not check for the second approval. If a second approval is not necessary, please apply the trivial label.
• Do the proposed changes actually accomplish desired goals? Also manually run the affected example notebooks, if necessary.
• Do the proposed changes follow the STScI Style Guides?
• Are tests added/updated as required? If so, do they follow the STScI Style Guides?
• Are docs added/updated as required? If so, do they follow the STScI Style Guides?
• Did the CI pass? If not, are the failures related?
• Is a change log needed? If yes, is it added to CHANGES.rst?
• Is a milestone set?
• After merge, any internal documentations need updating (e.g., JIRA, Innerspace)? 🐱

[larrybradley]

Thanks, LGTM. Can we also change "Colormaps" to "Colormap"?

[pllim]

@larrybradley , done. Please approve if you are happy with this.

[codecov]

Codecov Report

Merging #1406 (026a1c3) into main (b3c0a24) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1406   +/-   ##
=======================================
  Coverage   85.11%   85.11%           
=======================================
  Files          91       91           
  Lines        8308     8310    +2     
=======================================
+ Hits         7071     7073    +2     
  Misses       1237     1237           

Impacted Files	Coverage Δ
jdaviz/core/template_mixin.py	91.35% <100.00%> (+0.02%)	⬆️

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[larrybradley]

Thanks, @pllim

[pllim]

Thanks for the reviews!