[WFLY-490] Misc read-resource-description improvements

This is all feedback from Heiko Braun. 

1)
In r-r-d access-control for attributes don't separate between read-config/-runtime and write-config/-runtime. Simple 'read' or 'write' will do.

2) The 'attributes' parameter we added did not work so well when :read-resource-description(access-control=true, operations=true) since that then includes all the parameters again for the operations. I've removed the 'attributes' parameter, and made access-control use an enum:
*NONE - default and does not include access-control (similar to access-control=false, before this patch)
*COMBINED_DESCRIPTIONS - includes access-control and the full description (similar to access-control=true, before this patch)
*TRIM_DESCRIPTIONS - includes access-control, but trims the resource description (similar to access-control=true,attributes=false, but also removes the resource description and all operations from the output. If operations=true, the ops are included in the access-control section)