Remove settings that should not be altered

We have some settings that should not be altered and should be excluded from AdminFE at this time. This list is a work in progress.

• > HTTP Signatures settings > Adapter
• > Instance > Federation publisher modules
• > Job Queue > Repo (we are unlikely to support a separate database just for Oban job queues at this time)

mentioned in merge request pleroma!2540 (merged)

mentioned in merge request !131 (merged)

closed via merge request pleroma!2540 (merged)

mentioned in commit pleroma@64b3d81e

mentioned in commit dd4b5b2f

marked the checklist item > HTTP Signatures settings > Adapter as completed

marked the checklist item > Instance > Federation publisher modules as completed

marked the checklist item > Job Queue > Repo (we are unlikely to support a separate database just for Oban job queues at this time) as completed