OAK-8190 : initial commit....

[Angela Schreiber <an...@adobe.com.INVALID>]

hi oak-dev

i am planning to push a initial version of the authorization model for OAK-8190 [0] later today or early next week. while it is still work in progress and some pieces (notably benchmarks and documentation) are still missing, i feel that it is stable enough to be committed now. the commit doesn't affect any existing modules as all blocking issues have been resolved separately.
while the original driver for that issue was to be able to mount system users and their permissions in a separate read-only mount, the approach chosen allows to adjust the model for any type of principals with very limited effort... in detail documentation on the design, inner working, configuration options and limitations will be available with the regular oak security documentation later on.

kind regards
angela

[0] https://issues.apache.org/jira/browse/OAK-8190