Add tagging system to projects/allocations/resources

[cecilialau6776]

The Tag model is built to be added as a ManyToMany field onto any arbitrary model. This PR adds it to Project, Allocation and Resource.

The allowed_models field dictates which tags show up as part of editing in the UI - this is not validated anywhere else. An admin could add a tag to a model that's not in the list through the admin panel or the shell.

The project detail and allocation detail pages have a card for tags, while resources can only have their tags edited via the admin panel.

Permissions on tags can be set such that:

• Anyone can view
• Project managers can add/remove the tag
• Only superusers can view/add/remove

Only administrators/superusers can create tags, and only through the admin portal.

Potential future features:

• searching objects (projects/allocations) by tag
• more robust permissions

[simonLeary42]

After doing a deep dive on allocation statuses, I came to the conclusion that most of the statuses didn't really belong as statuses. They belong as tags. When a PI requests an allocation renewal, the allocation shouldn't stop being Active and start being Renewal Requested, it should stay as Active and just get an extra tag.