[16][IMP] Manage quantities correctly in case of kit in RMA

[florian-dacosta]

I need to manage kit (phantom bom) sometimes in my RMA.
in rma_sale_mrp, there is already an option at company level allowing to add a rma line with the kit of multiple rma lines with the component, when creating the rma line from a sale order line.

But the to receive/deliver quantity are not managed for this kind of product.

This PR aims to solve it, at least for basic cases.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 95.83333% with 1 line in your changes missing coverage. Please review.

Project coverage is 82.14%. Comparing base (bb16136) to head (f8f7f75).
Report is 49 commits behind head on 16.0.

Files with missing lines	Patch %	Lines
rma/models/rma_order_line.py	92.85%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             16.0     #618      +/-   ##
==========================================
+ Coverage   81.36%   82.14%   +0.78%     
==========================================
  Files         159      162       +3     
  Lines        5425     5875     +450     
  Branches      874      742     -132     
==========================================
+ Hits         4414     4826     +412     
- Misses        769      807      +38     
  Partials      242      242              

Files with missing lines	Coverage Δ
rma_sale_mrp/models/rma_order_line.py	70.37% <100.00%> (+17.42%)	⬆️
rma/models/rma_order_line.py	83.66% <92.85%> (+1.46%)	⬆️

... and 9 files with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 2d6b612...f8f7f75. Read the comment docs.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.