Proposed Additions for Team Synchronization and External Group Support

[WolfgangFischerEtas]

This pull request introduces support for connecting Otterdog-managed teams to identity provider (IdP) groups using GitHub Enterprise Cloud’s team synchronization and external groups features. These additions allow organizations to manage team membership through their IdP, ensuring consistent and automated provisioning of access.

The following new fields are added to the team configuration schema:

• team_sync_id — The unique identifier of the IdP group linked to the GitHub team. This value corresponds to the group ID provided by the identity provider and is used by GitHub Enterprise Cloud to synchronize membership automatically.
• team_sync_description — A human‑readable description of the IdP group associated with the team. This helps document the purpose or scope of the external group within the configuration.
• team_sync_name — The display name of the IdP group connected to the GitHub team. This is typically the group’s canonical name as defined in the identity provider.
• external_groups — The identifier of an external group provisioned through the organization’s IdP and mapped to the GitHub team. This field enables Otterdog to manage teams that rely on external group provisioning rather than direct team synchronization.

Together, these fields enable otterdog to fully support GitHub Enterprise Cloud’s mechanisms for automated team membership management via identity providers.