orch: refactor boolean handling in drive group spec

orch: refactor boolean handling in drive group spec

The intent of 42721c03ee6f was to address an issue where boolean
parameters weren't handled correctly.

I noticed that a parameter (`tpm2`) was missed, which made me realize
that maintaining a list of these boolean parameters is necessary.

To simplify things, we should only accept `"true"` or `"false"` (in any case),
allowing us to avoid the need to maintain a list of boolean parameters.

This change introduces a `list_drive_group_spec_bool_arg` to store boolean
arguments related to drive group specifications, simplifying the validation
process for boolean values by directly checking if the values are 'true' or 'false'.

Fixes: https://tracker.ceph.com/issues/68045
Signed-off-by: Guillaume Abrioux <gabrioux@ibm.com>