Feat: Organize all labels into groups

[KaterynaBasik]

PO: The purpose of labels is to group several processes, e.g. to the Gullfaks asset, to make it easier to find and/or follow-up. Labels can be used to filter processes from the landing page (by clicking "Filter by label" or selecting a label).

Existing labels are:

• Organisation at L1-level (e.g. EPN, MMP, TDI)
• Functional areas (e.g. Subsurface, Finance and Control, Supply Chain Management)
• Installation names (e.g. Peregrino, Oseberg, Snøhvit)

Current list of labels looks like this:

It would be nice to have all labels organized somehow

[QiJin-Bouvet]

Some proposals for this feature:

• group labels into different categories: projects related, organization related, functional area related, installation names, and so on
• ask user to select label category first, from a dropdown menu, for example, and then select labels from that category
• allow user to select labels from multiple categories