[Rock-Ons] Allow mapping/mounting of individual folders instead of only shares

[Marenz]

I think technically it's not a problem. And I think there are many use cases where it would makes either easier or simpler for the end user:

• The "shares" screen wouldn't be as cluttered
• You can create a hierarchy, for example have one "rock-ons-configs" share with a folder for each rock-on instead of a whole share for each rock-on config
• My media might be in a share "media" with subfolders for audio, video and images. If I want to have a rock-on that handles only images, I can't just mount my media folder as it can't handle the other data. Often you can work around that by specific configurations in the rock-on, but it's extra work that wouldn't be required anymore with this.
• It might make auto-creating config-storage folders easier (this idea was mentioned in another related ticket, only for shares)

[FroggyFlox]

You're making very good points there, @Marenz, and I completely agree with you; that's a great idea.

We actually have had this brought up not too long ago and it received some positive feedback from other users as well so I believe it's definitely something we should add. Here's the issue in question (it was posted in our rockon-registry repo):
rockstor/rockon-registry#95

I unfortunately haven't had time to think about the details of its implementation and how to best integrate it in our existing structure, but we should work on that, yes. Here's some pointers on how the rock-ons framework is organized, for those curious and wanting some "getting started" pointers on rock-ons:
https://forum.rockstor.com/t/rock-on-framework-implementation/6288?u=flox

Sorry for not being able to bring more to the table at the moment.

[FroggyFlox]

Linking to a forum post detailing the overall improvements needed; the current issue would be part of such rework:
https://forum.rockstor.com/t/suggestion-better-clearer-wizard-and-or-folder-structure/8607/2.