Add doc where we provide mapping of supported share features by each specific
share driver.
In this commit up-to-date information is provided only for Generic driver.
All other are expected to be updated afterwards.
Change-Id: I9645857b59563084b76a94308f4523e37b860201
Glossary should be used to describe common terms used in Manila's
documentation. Starting using it for "manila-share", "manila-api" and
"manila-scheduler".
Change-Id: I288332f5b599c9c78d45f0102e4d2a20753af3a6