Vectorize support + nonAstra databases for v1.2.0

[hemidactylus]

Non-Astra environment awareness:

• astrapy.constants.Environment enum for the "environment" parameter to client, etc
• flexibility and adaptive defaults for data api url
• environment knowledge trickles throughout all classes (client, admins, databases)
• DataAPIDatabaseAdmin class (i.e. for namespace CRUD)
• (internal) astrapy.api_commander.APICommander
  (internal) astrapy.api_options.{BaseAPIOptions, CollectionAPIOptions}
  $vectorize support:
• "service options" for creating/retrieving collections, covering $vectorize needs
• embedding_api_key parameter to collection (for "header" usage)
  collection-level timeout parameter (overridable in single method calls)
  expand "projection" type to include slice projections
  client.get_database can accept an API endpoint directly
  insert_many and bulk_write default to ordered=False