Possibility to enforce the execution order in resource_group

What does this MR do?

This MR introduces the new process modes to resource groups, specifically support Oldest First and Newest First mode that executes the jobs in a specific order. Please see the full explanation on these modes in the documentation.

This MR specifically contains the following changes:

• It adds a database migration to add process_mode column (enum) to ci_resource_groups table.
• It extends the upcoming_processables to evaluate the jobs in a desired order.
• It introduces the basic policy for resource group to define the permission on the read and edit actions.
• It adds two new API endpoints to read and edit a resource group.

Related #202186 (closed)

Schema Migration

shinya@shinya-B550-VISION-D:~/workspace/thin-gdk/services/rails/src$ tre bin/rails db:migrate:redo VERSION=20210916132547
INFO: This script is a predefined script in devkitkat.
WARNING: This installation of GitLab uses a deprecated syntax for 'config/database.yml'. The support for this syntax will be removed in 15.0. More information can be found here: https://gitlab.com/gitlab-org/gitlab/-/issues/338182
== 20210916132547 AddProcessModeToResourceGroups: reverting ===================
-- remove_column(:ci_resource_groups, :process_mode)
 -> 0.0008s
== 20210916132547 AddProcessModeToResourceGroups: reverted (0.0009s) ==========

== 20210916132547 AddProcessModeToResourceGroups: migrating ===================
-- add_column(:ci_resource_groups, :process_mode, :integer, {:default=>0, :null=>false, :limit=>2})
 -> 0.0012s
== 20210916132547 AddProcessModeToResourceGroups: migrated (0.0012s) ==========

Timing: The query has been executed. Duration: 22.027 ms https://gitlab.slack.com/archives/CLJMDRD8C/p1630566276492300

Screenshots or Screencasts (strongly suggested)

Here is the pipeline transition with each process mode with the following gitlab-ci.yml.

Unordered

semaphore

Oldest First

fifo

Newest First

lifo

How to setup and validate locally (strongly suggested)

Launch GDK and run a pipeline with the following .gitlab-ci.yml

build:
  stage: build
  script: sleep $((RANDOM % 10))

deploy:
  stage: deploy
  script: echo
  environment: production
  resource_group: production

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.
• This change is backwards compatible across updates, or this does not apply.

Availability and Testing

• I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• I have tested this MR in all supported browsers, or it's not needed.
• I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

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Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team