Enhance Access Groups

[Petr Nejedly]

1. User defined Access Groups. The group definitions need to be nothing more than group names, with all access control defined within the Renderer and Library settings as currently.

2. Assigning Access Groups for each item in the Presentation settings. For example, we have an Access Group called "Kids" which serves their XBox, for which we only want to show content under the "Series" category. By excluding the "Kids" Access Group from other enabled categories they would only see "Series". Another Access Group ("Parents" for example), might be included in the categories "Series", "Movies" and "Folders"

3. Clear display of assigned Access Groups in the Renderers, Folders and Presentation settings, instead of having to navigate through a right click menu. Perhaps even a new summary view available for Access Groups showing which renderer, folders and presentation categories are enabled for them.

4. "Last Viewed" on a per Access Group basis. For example if two groups are watching the same series but at different episodes, Serviio should track the last watched episode for each group.

[Petr Nejedly]

This will be probably replaced by multi user support

[Petr Nejedly]

Duplicate of #931.