[FE-111] Add Field Engineering Service Docs

[felixshiftellecon]

Note

You may find that there are errors for the vale/lint job that are unrelated to your change.
Vale checks the whole file when a change is made so if there are existing issues on the page they will be flagged.
You can ignore lint errors outside your changes and the CircleCI docs team will address them for you.
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Description

Added a section for field engineering services, and overview page, and pages for each service.

In draft PR for content review by the FE team, some items in checklist below will need to be confirmed before an official review.

Reasons

There is no public facing documentation on the services provided by the field engineering team. Customers have to ask for the catalogue, this is intended to make the service list self serve.

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).