Kit editing: modifying project associations

[wasade]

It should be possible to update project associations. This should include:

• making a kit a microsetta kit
• adding a project association

Removal of a project association is deferred. It's not obvious if this should be supported.

[specsdom]

Modification features would ideally include:

• Option to select/input a barcode (and/or barcodes)
• Information displayed about what project the barcode(s) are currently associated with
• Option to choose which project to update and move the barcode(s) to