Add mount-point suggestion from Douglas Russell (Fix #9801)

As suggested by Douglas, if the mounted shared disappears or
is not present, OMERO will try to use the mount point instead.
Move shares section up
Fix .. note indentation
Merge pull request #295 from bpindelski/rebased/develop/deploy-web-fix

Fix .. note indentation (rebased onto develop)
Merge pull request #293 from joshmoore/rebased/develop/9801-mounts

Add mount-point suggestion from Douglas Russell (Fix #9801) (rebased onto develop)