DPL-106 Add unique constraint to barcode+location in destination_wells [+1 Biosero from UAT]

[emrojo]

User story
As a PSD developer I want to add a unique constraint for barcode and location in destination_wells so we don't allow duplicated wells in the same position across different run_ids

Who are the primary contacts for this story
Eduardo Martin
Harriet Craven
Andrew Sparkes

Acceptance criteria
To be considered successful the solution must allow:

• Block any attempts to create a duplicate well in the same position for a barcode

Dependencies
This story is blocked by the following dependencies:

• #<issue_no.>
• sanger/#<issue_no.>

References
This story has a non-blocking relationship with:

• #<issue_no.>
• sanger/#<issue_no.>

Additional context
Add any other context or screenshots about the feature request here.