Uses the below schema to supply mounter specific map/unmapOptions to the
nodeplugin based on the discussion we all had at
https://github.com/ceph/ceph-csi/pull/2636
This should specifically be really helpful with the `tryOthermonters`
set to true, i.e with fallback mechanism settings turned ON.
mapOption: "kbrd:v1,v2,v3;nbd:v1,v2,v3"
- By omitting `krbd:` or `nbd:`, the option(s) apply to
rbdDefaultMounter which is krbd.
- A user can _override_ the options for a mounter by specifying `krbd:`
or `nbd:`.
mapOption: "v1,v2,v3;nbd:v1,v2,v3"
is effectively the same as the 1st example.
- Sections are split by `;`.
- If users want to specify common options for both `krbd` and `nbd`,
they should mention them twice.
Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>