doc: kill sphinx warnings

doc: kill sphinx warnings

* doc/release-notes.rst: escape asterisks not used for inline emphasis
    fix bad hyper links
* doc/rados/troubleshooting/troubleshooting-osd.rst: escape asterisks
    not used for inline emphasis
* doc/radosgw/index.rst: add orphan docs to toc
* doc/dev/perf_histograms.rst: indent block quote
* doc/install/manual-freebsd-deployment.rst: fix block quotes
* doc/mgr/administrator.rst: escape asterisks not used for inline emphasis
* doc/start/quick-rbd.rst: add missing hyper link target

Signed-off-by: Kefu Chai <kchai@redhat.com>