Config Ref: Improve Compute scheduler description

Improve the compute scheduler section:
* Add missing filters
* Improve wording for some filters
* Fix default values
* use spaces around "=" in programlistings
* Fix markup

Change-Id: I69c38ba5cba1c04c4a51c519de561083bb59619f
Closes-Bug: #1304089
Closes-Bug: #1361860
Closes-Bug: #1361591
Closes-Bug: #1362425
Merge "Config Ref: Improve Compute scheduler description"