Added annotation to disable adding writable vSMB or plan 9 file shares
to a UVM.

Grouped together setting common *COW options into a common function to
improve readability.

Added tests for proper initialization and processing of common creation
options, as well as functional tests for disabling writable shares.
Currently, functional tests do not run smoothly.

Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com>

Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com>

Can now expand an annotation into several sub annotations to toggle
groups of features on and off. Added tests for this as well.

Moved general annotation handling and parsing from `internal/oci/uvm.go`
to `internal/oci/annotations`, and updated tests.

Combined common OCI and gMSA tests together with subtests
Made capitalization for GMSA consistent throughout.

Removed changes to test/functional/utilities

Removed unnecessary error return.

Removed creation option for disabling gMSA and instead parse the
annotation directly from the spec.

Signed-off-by: Hamza El-Saawy <hamzaelsaawy@microsoft.com>