Officially 'install' the 'google_tag_container' entity type

Problem/Motivation

Release 8.x-1.2 of this project includes a feature change to allow multiple containers. This was implemented by adding a configuration entity type, namely the 'google_tag_container' entity type.

Drupal prefers each entity_type to be officially 'installed' which simply means entity type listeners are given an opportunity to act on the new arrival. Afterwards, the entity type is recorded in the database. Absent this 'install' action, the status report page (at 'admin/reports/status') will include an 'error' indicating the 'entity type needs to be installed'. The text accompanying this 'error' uses the misleading phrase 'mismatched entity definition'. Although the entity type may not be recorded in the aforereferenced database table, it is recorded in the config and cache_config tables and nothing [to my knowledge] fails to work with the module. Drupal is indeed aware of the entity type, the container add and update forms work fine, and the tags are inserted on a page request according to the container settings.

Proposed resolution

Keep everyone happy, send out the birth announcement, and record the birth in the registrar.

NOTE: There is no need to reinstall the module as some have suggested on a separate issue in order to make the module work correctly. As stated above it is working correctly. However, if the 'error' message on the status report causes a loss of sleep, then by all means reinstall. Or apply the forthcoming patch on this issue to your code base.

For additional comments related to this task, refer to comments 12-21 on #3069679: google_tag.container config entities have an incomplete config schema.

Remaining tasks

None.

User interface changes

None.

API changes

None.

Data model changes

None.