NEXUS-6310: NEXUS-7603: Tika 1.6
NEXUS-6310: Align NX mime rules with Tike 1.6

For example, use of app/gzip over older app/x-gzip, etc.
NEXUS-6310: Redo change from 7514b292756b703a6f9916247e8f7581efc676de

As it was not correct. ZIP needs higher priority, as with change
from 7514b292756b703a6f9916247e8f7581efc676de all ZIPs became
app/java-archive's
Related fix: media type registry was rebuilt over and over again

Instead of that, get hold on tika config and build it once and use it
always
NEXUS-7628: On delete of collection purge NFC for children
Merge pull request #842 from sonatype/nexus-2.11.x-NEXUS-7628-collection-delete

NEXUS-7628: On delete of collection purge NFC for children
Merge pull request #836 from sonatype/nexus-2.11.x-NEXUS-6310-tika-1.6

NEXUS-6310: NEXUS-7603: Tika 1.6
* resurrect lost purge broken files scheduler tasks
* some cleanup in comments and user facing text
* inline simple private method used only once
Merge pull request #838 from mkristian/resurrect-lost-scheduler-task-for-ruby-proxy

* resurrect lost purge broken files scheduler tasks
Merge remote-tracking branch 'origin/nexus-2.11.x' into nexus-2.11.x-NEXUS-7608-rubygems-trials