[Feature] Support more explicit permissions on ServiceAPI

[fmigneault]

Service of type ServiceAPI allows read/write/read-match/write-match permissions.

It should be extended to allow explicit permissions as standard request methods, ie: GET, POST, DELETE, PUT, etc. since this is what it already filters, but combining multiple method types under read/write categories

For backward compatibility reasons, the original 4 permissions should remain.
The service would then need to validate for example that GET request is granted access if either combination between explicit GET or read-category (on any parent route) or GET-match/read-match (on exact route) is given.
An admin who desires to restrict more granular permissions would have more flexibility to do so with whichever variant better fits his need.

[fmigneault]

relates to #342