Cleanup of factory reference manual section

[kprosise]

Style guide lines applied. Removed link to the Yocto Project layers section which is part of the LmP reference manual; this was done to make navigation less confusing, and to keep sections focused.

The section on Factory Sources was placed before the Factory Definition, for better explanatory flow.

QA steps: Ran linter and addressed issues where possible/appropriate. Checked html output in browser, no obvious rendering issues discovered. Ran linkcheck.

This commit addresses FFTK-2790
This commit addresses FFTK-1880
This commit applies to FFTK-2732
This commit applies to FFTK-2730
This commit applies to FFTK-988

Readiness

• Merge (pending reviews)
• Merge after date or event
• Draft

Overview

Why merge this PR? What does it solve?

Checklist

Optional. Add a 'x' to steps taken.
You can fill this out after opening the PR. "Did I..."

• Run spelling and grammar check, preferably with linter.
• Avoid changing any header associated with a link/reference.
• Step through instructions (or ask someone to do so).
• Review for wordiness
• Match tone and style of page/section.
• Run make linkcheck.
• View HTML in a browser to check rendering.
• Use semantic newlines.
• follow best practices for commits.
  • Descriptive title written in the imperative.
  • Include brief overview of QA steps taken.
  • Mention any related issues numbers.
  • End message with sign off/DCO line (-s, --signoff).
  • Sign commit with your gpg key (-S, --gpg-sign).
  • Squash commits if needed.
• Request PR review by a technical writer and at least one peer.

Comments

Any thing else that a maintainer/reviewer should know.
This could include potential issues, rational for approach, etc.

[doanac]

Docs for bc84a46 are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2484/docs/artifacts/html/index.html

[quaresmajose]

The image lmp-base-console-image from the public LmP is mentions in some places but I think the default image used in every factory is the lmp-factory-image.

[angolini]

Only few suggestion

[kprosise]

review suggestions

[doanac]

Docs for 40bb1ab are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2485/docs/artifacts/html/index.html

[doanac]

Docs for 34ea46b are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2486/docs/artifacts/html/index.html

[doanac]

Docs for 55be7fd are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2487/docs/artifacts/html/index.html

[doanac]

Docs for 5c97cd7 are browsable at: https://ci.foundries.io/projects/fio-docs/builds/2488/docs/artifacts/html/index.html