Tools: remove dependency on PVE::Cluster

Tools: remove dependency on PVE::Cluster

by moving parse_sid to PVE::HA::Env, with the default implementation in
PVE::HA::Config.

the bash completion methods use PVE::HA::Config (and PVE::Cluster), but
the corresponding use statements are only in PVE::CLI::ha_manager, where the
bash completion is actually used.

Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>