[FEATURE] Be able to set the disk size and type of the Agent/Manager from the UI

[Raimund58]

Is your feature request related to a problem? Please describe.

If I start 20 agents I end up with 4000GB of diskspace even if my .blend is only 500mb.
I also would like to be able to choose my favored disk type (SSD or such)

Describe the solution you'd like

I would like to be able set the size of the disk.

Describe alternatives you've considered

Currently I change the code in \2.91\scripts\addons\blendnet\BlendNet\providers\gcp\__init__.py

[rabits]

Agree, useful & simple to implement by using provider settings (still in dev in #137)