[14.0][IMP] rma: add date to rma_order_line

[DavidJForgeFlow]

Adds date to rma lines. Missing migration script to get default values in already existing databases.

[codecov-commenter]

Codecov Report

Merging #432 (f155deb) into 14.0 (a8727de) will decrease coverage by 0.04%.
The diff coverage is 68.75%.

Additional details and impacted files

@@            Coverage Diff             @@
##             14.0     #432      +/-   ##
==========================================
- Coverage   80.72%   80.68%   -0.04%     
==========================================
  Files         156      156              
  Lines        4862     4878      +16     
  Branches      897      904       +7     
==========================================
+ Hits         3925     3936      +11     
- Misses        728      730       +2     
- Partials      209      212       +3     

Files	Coverage Δ
rma/models/rma_order_line.py	78.40% <100.00%> (+0.18%)	⬆️
rma/models/rma_order.py	82.78% <61.53%> (-2.01%)	⬇️

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[AaronHForgeFlow]

When the date_rma is set in the rma group all the lines should take that date I think.

[AaronHForgeFlow]

@DavidJForgeFlow as long the date is in the rma group I think it makes sense to be consistent with the date in the lines, do you agree?

[AaronHForgeFlow]

The same PR is merged in v16 so I am merging this here to keep branches even