Pulp

Problem: OpenAPI schema test is unreliable between different installs

Solution: Remove the test

re: #4104 https://pulp.plan.io/issues/4104

Problem: REST API docs are poorly organized

Solution: Break up REST API docs into sections

This patch modifies the OpenAPI schema. It introduces the concept of Tags. Each tag represents a type of resource in Pulp. E.g. Artifacts, Content, Remotes, Publishers, etc.

This patch also improves the 'summary' field for each operation also. This is achieved with a new custom inspector class that drf_yasg can use to build the OpenAPI schema.

This patch also adds a new 'restapi.html' page to the static docs. This new page uses ReDoc and the OpenAPI schema to display the REST API docs.

re: #4104 https://pulp.plan.io/issues/4104