NEXUS-5714: Status resource without perms

Introduced "perms" query parameter on status resource, that is
checked for presence only (hence, without, or with any value
works). If "perms" query parameter is present, the status
resource will emit permission related info, as it behaved
before this change.

Without this query parameter, status resource emits only what
it's original intent was.

Measured (before vs after) response time differences is 300ms vs 150 ms,
payload size differences is 7009 byte vs 1152 byte

Note: tested with OSS. These would just grow with Pro, as
delivered permissions are extended by Pro plugins like staging and
others.
NEXUS-5714: Fixing one failing IT

There was one IT that made use of permissions in status
resource (to verify that perms are 15 when security is shut
down).
Merge pull request #861 from sonatype/nexus-5714-status-resource

[2.6] NEXUS-5714: Status resource without perms