Create biganimal_regions data source

[serdardalgic]

Currently, we have biganimal_region data source, and as explained in #131, it should actually be renamed.

biganimal_region resource and data sources use the /projects/{projectId}/cloud-providers/{cloudProviderId}/regions endpoint to read, list, activate, deactivate the regions.

However, the /projects/{projectId}/regions endpoint provides further information about the regions. From this endpoint, users can

• filter by (multiple) status
• filter by (multiple) continents
• filter by (multiple) CSPs (which is already possible with the biganimal_region data source)
• Additional outputs such as customerLogsUrl, customerMetricsUrl and clusterCount are also available at this endpoint.

biganimal_regions data source would use the /projects/{projectId}/regions endpoint.