Allow PI to request changes to resource allocation attributes

[knikolla]

As a PI, I would like the possibility of requesting a change to resource allocation attributes after a resource allocation has been created and approved. This request would require approval from administrators before being executed.

Resource allocation attributes are used to express quotas/limitations of a resource allocation on a resource, and in a cloud environment where some resource allocations can be very long lived, should be allowed to scale up as usage and requirements grow.

[dsajdak]

Possibly related to or in place of #287

[dsajdak]

This is a high level diagram of what we'd want the process to look like. We want to allow the PI/manager to make change requests on SOME allocation attributes, as well as the end date, and possible other things. This sketches out two potential ways to accomplish this:

This is a rough idea of what option 2, described in above diagram, could look like:

We'll need to think about the various resource types and what attribute types they may have as well as what allocation attribute types might be available for those resource types to ensure we test all possible scenarios. As described in the text of the first diagram, we'll need a way to define that an attribute can have a change request and if not, it is not possible to be modified in this process. That needs to be configurable on the attribute type because admins have the ability to add new attribute types: