Ceph CSI v1.2.0 Release

Release Issue # #393

Changelog or highlights:

*) Cephfs: Use ceph kernel client if kernel version >= 4.17
*) implement grpc metrics for ceph-csi
*) Add xfs fstype as default type in storageclass
*) Add support to use ceph manager rbd command to delete an image
*) e2e: correct log format in execCommandInPod()
*) Add 'gosec' to the static-checks
*) switch to cephfs, utils, and csicommon to new loging system
*) utility to trace backend volume from RBD pvc
*) Implement context-based logging
*) implement klog wrapper
*) unmap rbd image if connection timeout.
*) start controller or node server based on config
*) fix: Adds liveness sidecar to v1.14+ helm charts
*) Prometheus liveness probe sidecar
*) Wrap error if failed to fetch mon
*) provisioners: add reconfiguring of PID limit
*) Use "rbd device list" to list and find rbd images and their device paths
*) Update Unstage transaction to undo steps done in Stage
*) Move mounting staging instance to a sub-path within staging path
*) e2e: do not fail to delete resources when "resource not found"
*) remove post validation of rbd device

Many other bug fixes, code improvements, README updates are also part of this release.