Updated Protocol Designer section in Flex manual

[emilyburghardt]

Overview

Draft PR as I start to add text over (+ some formatting changes for mkdocs).

Test Plan and Hands on Testing

Changelog

TODO: remove MOAM section in PAPI exclusive features; remove remaining comments.

Review requests

Risk assessment

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 24.24%. Comparing base (c8d5916) to head (15207b6).
⚠️ Report is 39 commits behind head on edge.

Additional details and impacted files

@@            Coverage Diff             @@
##             edge   #18893      +/-   ##
==========================================
- Coverage   24.24%   24.24%   -0.01%     
==========================================
  Files        3370     3370              
  Lines      296410   296418       +8     
  Branches    37690    37694       +4     
==========================================
  Hits        71868    71868              
- Misses     224518   224526       +8     
  Partials       24       24              

Flag	Coverage Δ
protocol-designer	18.94% <ø> (ø)
step-generation	5.37% <ø> (-0.01%)	⬇️

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see 1 file with indirect coverage changes

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[ecormany]

Handful of suggestions and requests; nothing major.

[ecormany]

Incorporating all these changes into #19151.