[BUG] Setup script fails if SEEN and RG is in a different sub than LA

[piaudonn]

The current script assumes that the Azure Subscription ID is the same for the RG of SEEN and the RG of the Log Analytics workspace. Because of that it cannot grant the RBAC Log Analytics Reader to the 3 modules.

Current workaround is to manually add the managed identities of the module into the Log Analytics Reader role of the LA workspace.

Proposed fix is to add a parameter for the sub ID of the LA workspace, assume it is the same when not provided and add a sub id parameter to the set RBAC function.

Go to work @piaudonn !