[NEXUS-5651] Send 401 in case of an AuthroizationException and user not authenticated (not logged in)

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5651] Filter "/service/siesta/**" through  "noSessionCreation,authcBasic" filters

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5651] Introduce FilterChain, a mapping between path pattern and a filter expression

+ convenience guice module for easy binding

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
[NEXUS-5651] Map "/service/siesta/**" ->  "noSessionCreation,authcBasic" filters

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Move timeline/feeds UI from core to plugin
Fix edge cases for classnames (no namespace)
Add events for plugins to add to or change the server settings view
Typo nexus.anonynmous -> nexus.anonymous

Signed-off-by: Alin Dreghiciu <adreghiciu@gmail.com>
Update docs
Merge pull request #783 from sonatype/move-timeline-ui

Move timeline UI from core to plugin
Add docs
Merge pull request #796 from sonatype/server-config-plugin-contrib

REVIEW: Add event for plugins to add to or change the server settings view
Merge pull request #800 from sonatype/nexus-5651-siesta-authz

REVIEW: [NEXUS-5651] Siesta resources authorisation
Fix for intermittent NPE in routing tests.
Problem was that UT/ITs had no more means to detect
when "boot is done", and sometimes they kicked in
too early, with expectations (or without proper
checks) causing NPEs with carelessly loading
up prefix files without checking for their
existence (as "they should exist").

Reason was that boot process of routing
did not finish yet, as in 1st pass all
the prefix files are created for hosted
repositories for example.
Merge remote-tracking branch 'origin/master' into routing-fixes