Permissions that should be configurable

I found no issue where something like a list of missing permission configuration options are listed.

Here is my list of which permission options i miss:

- System Menu access (more granularity)
- Alerts and Conditions (more granularity)
- Stream and Dashboard editing needs more granularity (start, stop, alert, rules, index sets, remove messages from default stream ...)
- API Access (In general to allow every API only via Authentication)

## Context
At the Moment our Non-Admin users can see too much of the internals, and maybe misconfigure something when i grant them edit permissions. So we have to do all small changes, like Alert adding and Dashboard Building/Changing via an Admin.

## Your Environment
Graylog 2.2.0+d9681cb on syslog.xyz.local (Oracle Corporation 1.8.0_121 on Linux 3.10.0-327.22.2.el7.x86_64) [footnote: THX for the great 2.2 release!!]