[MIG][9.0] contract_invoice_merge_by_partner module

[cubells]

• Update README
• Update views
• Update tests

cc @Tecnativa

[luismontalba]

Functionality tested on runbot (I've loaded the Sales Management application to access contract menu)

[chienandalu]

functionality tested 👍

[rafaelbn]

Tested, thanks

[mourad-ehm]

Hi @pedrobaeza, Do you know why this module has not been migrated in the recent versions ?
We have a customer need to merge invoices generated by contracts (by some criteria). I didn't see that this need is covered by the contract modules of v14.

[pedrobaeza]

We haven't used since this version, but it's still interesting and it's not covered in the base module. The architecture is not the same, so the migration won't be direct I'm afraid.

[mourad-ehm]

Thank you @pedrobaeza for your response.
We should propose a solution to our customer for merging contracts in the same way of merging invoices.
But we don't delete the the merged contracts but only cancel contract lines (by probably use a renew line method).
In fact, contracts can be merged a long time after their creation, and we want preserve history of invoicing of merged contracts.
If it accepts solution, we w'll propose new module.

[pedrobaeza]

I don't have clear the possible derivations of such thing, but putting that contract merging in a separate module will avoid debates.