nrpe checks

[Adam Dyess]

Please make this charm relatable with nrpe-external-master to the nrpe charm.

Some useful checks would be ..

are all the nfs exports active?
is nfs-ganesha running on the vip holder
is manila-share running on the vip holder

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/charm-manila-ganesha/+/848219

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/charm-manila-ganesha/+/848219
Committed: https://opendev.org/openstack/charm-manila-ganesha/commit/65ca408318ac637ef4787e61d5ec48f4d4477502
Submitter: "Zuul (22348)"
Branch: master

commit 65ca408318ac637ef4787e61d5ec48f4d4477502
Author: Chi Wai, Chan <email address hidden>
Date: Tue Jun 28 14:56:50 2022 +0800

    Added NRPE checks for manila-ganesha charm.

    - added 3 basic checks to check: nfs connection, nfs services, and nfs shares
    - updated test bundles to include nrpe and nrpe-external-master for
      functional tests.

    func-test-pr: https://github.com/openstack-charmers/zaza-openstack-tests/pull/806

    Closes-bug: #1925975
    Change-Id: I4d3736300f75b9811f4f6525b5454c7e495ef566