Add serial groups examples to orchestration cookbook

[rosieyohannan]

Description

Added four comprehensive examples of using serial groups to the orchestration cookbook following the existing page structure.

Changes include:

• Recipe for preventing deployment conflicts with serial groups
• Recipe for ensuring database migrations run in sequence
• Recipe for controlling access to limited testing resources
• Recipe for maintaining version integrity with serial deployments

Each recipe follows the established cookbook format with Goal, Steps, and Notes sections.

Reasons

This change addresses Linear issue DOC-65, which requested examples of using serial groups in the orchestration cookbook. The serial groups feature allows controlled, sequential execution of jobs across an organization to prevent conflicts when accessing shared resources.

These practical examples help users understand when and how to implement serial groups in their CircleCI configurations.

Content checks

Please follow our style when contributing to CircleCI docs. View our style guide or check out our CONTRIBUTING.md for more information.

Preview your changes:

• View the Vale linter results, select the ci/circleci: lint job at the bottom of your PR. You will be redirected to the vale/lint job output in CircleCI.
• Preview your changes, select the ci/circleci: build job at the bottom of your PR and you will be redirected to CircleCI. Select the Artifacts tab and select index.html to open a preview version of the docs site built for your latest commit.

Take a moment to check through the following items when submitting your PR (this is just a guide so will not be relevant for all PRs):

Content structure:

• Break up walls of text by adding paragraph breaks.
• Consider if the content could benefit from more structure, such as lists or tables, to make it easier to consume.
• Consider whether the content would benefit from more subsections (h2-h6 headings) to make it easier to consume.
• Include relevant backlinks to other CircleCI docs/pages.

Formatting:

• Keep the title between 20 and 70 characters.
• Check all headings h1-h6 are in sentence case (only first letter is capitalized).

Linear Issue: DOC-65

  

[linear]

DOC-65 Add examples of using serial groups to the orchestration cookbook