Refactor rest

[mmacata]

See also #322

This PR

• moves some modules from the folder rest to a subfolder as no endpoint is directly assiciated with it:
  • the module user_auth
  • the module base_login
  • the module map_layer_base
  • the module renderer_base
  • the module resource_base
• ...

ATTENTION:
from actinia_core.rest.resource_base import ResourceBase is used in various actinia plugins!

-> This PR will stay draft, until the concerned addons are adjusted.