Fix support for SELinux volume mounts & case sensitivity

What does this MR do?

• Fix support for SELinux volume mounts https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label #4276 (closed)
• Fix case sensativity #4269 (closed)

Why was this MR needed?

Fix SELinux volume mounting

The regex does not match the following specification /src:/dst:Z|z which is a legit specification for SELinux https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label both Z and z mean different things and have a different meaning to the case sensitivity is important.

closes #4276 (closed)

Fix volume mounting for case sensitivity

Both for the volume spec and the setting up the Volume itself the string is being all lowered case which causes the following issues:

1. When a directory has lower/upper case characters
2. When using the Z mode for SELinux https://docs.docker.com/storage/bind-mounts/#configure-the-selinux-label

closes #4269 (closed)

Are there points in the code the reviewer needs to double check?

Does this MR meet the acceptance criteria?

• Documentation created/updated
• Added tests for this feature/bug
• In case of conflicts with master - branch was rebased

What are the relevant issue numbers?

Closes #4276 (closed) Closes #4269 (closed)