Import on demand credentials_lib in base_api.
Import on demand credentials_lib in base_api.

credentials_lib depends on oauth2client which had support for webflow authentication, which brings a lot of dependencies, all not used if user of the client manages its own credentials.

thobrla/apitools,google/apitools,pcostell/apitools,craigcitro/apitools,betamos/apitools,kevinli7/apitools,cherba/apitools,houglum/apitools