Show a more helpful error for import status

Closes #47365

See merge request gitlab-org/gitlab-ce!19467

Docs: add the documentation guidelines into its own dir

See merge request gitlab-org/gitlab-ce!19323

Rails 5 fix glob spec

Closes #47376

See merge request gitlab-org/gitlab-ce!19469

Adjust monitoring graphs to support widgets in EE

See merge request gitlab-org/gitlab-ce!18062

Use Github repo visibility during import while respecting restricted visibility levels

Closes #47189

See merge request gitlab-org/gitlab-ce!19450

Add Avatar API

Closes #45821

See merge request gitlab-org/gitlab-ce!19121

Rename Secret variables -> variables

See merge request gitlab-org/gitlab-ce!19309

GraphQL setup: Basic Project and Merge request endpoint

Closes #34754

See merge request gitlab-org/gitlab-ce!19008

Resolve "Upgrade from source documentation - golang version required"

Closes #47204

See merge request gitlab-org/gitlab-ce!19434

QA Tests for Auto DevOps

See merge request gitlab-org/gitlab-ce!19200

Show job logs in web IDE

Closes #46245

See merge request gitlab-org/gitlab-ce!19279

Migrate jobs in object_storage_upload queue

Closes gitlab-ee#4811

See merge request gitlab-org/gitlab-ce!19180

There's no need to add a redundant message to the errors if the
model is invalid. This cleans up the message as well for the importer.

- All definitions have been replaced by classes:
  http://graphql-ruby.org/schema/class_based_api.html
- Authorization & Presentation have been refactored to work in the
  class based system
- Loaders have been replaced by resolvers
- Times are now coersed as ISO 8601

Bump grape-path-helpers to 1.0.2 to get updated Rake task naming

See merge request gitlab-org/gitlab-ce!19474

Importing a project from GitHub for a project namespace that already exists
would show an unhelpful error, "An error occurred while importing project."
We now add the base message from Projects::CreateService when this fails.

Closes #47365

Merge branch '47196-actionview-missingtemplate-missing-template-projects-merge_requests-invalid-projects-merge_requests-application-invalid-pr' into 'master'

Resolve "ActionView::MissingTemplate: Missing template projects/merge_requests/invalid, projects/merge_requests/application/invalid, pr..."

Closes #47196

See merge request gitlab-org/gitlab-ce!19356

Resolve "Manual job's triggered by datetime is wrong"

Closes #46858

See merge request gitlab-org/gitlab-ce!19438

Add development documentation on how to generate a list of routes

Resolve "POST api/v4/projects/:id/pipeline should accept variables"

Closes #25045

See merge request gitlab-org/gitlab-ce!19124

Rails 5 fix unknown keywords: changes, key_id, project, gl_repository, action,…

Closes #47368

See merge request gitlab-org/gitlab-ce!19466

Resolve "[Rails5] Fix specs with "text/plain; charset=utf-8""

Closes #47378

See merge request gitlab-org/gitlab-ce!19462

moved values to constants