feat: create custom_form_options api

[abhinavk96]

Fixes #6407

Short description of what this resolves:

Changes proposed in this pull request:

• Modify Custom form schema according to Propose and Implement a schema for complex custom forms #6191
• Introduce custom form options

[abhinavk96]

To be reviewed, after I test the functionality while developing client side logic on FE in parallel, to be in WIP until then.
Migration file missing intentionally, still working on some fields.

[codecov]

Codecov Report

Merging #6408 into development will increase coverage by 0.07%.
The diff coverage is 85%.

@@               Coverage Diff               @@
##           development    #6408      +/-   ##
===============================================
+ Coverage        64.41%   64.49%   +0.07%     
===============================================
  Files              288      291       +3     
  Lines            15058    15117      +59     
===============================================
+ Hits              9699     9749      +50     
- Misses            5359     5368       +9

Impacted Files	Coverage Δ
app/api/schema/custom_form_options.py	100% <100%> (ø)
app/api/schema/custom_forms.py	100% <100%> (ø)	⬆️
app/models/custom_form.py	92.68% <100%> (+1.01%)	⬆️
app/api/__init__.py	100% <100%> (ø)	⬆️
app/models/custom_form_option.py	66.66% <66.66%> (ø)
app/api/custom_form_options.py	77.77% <77.77%> (ø)

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[abhinavk96]

@iamareebjamal made the requested changes.