Apply minor updates and fixes to documentation

[kprosise]

Screenshots updated for getting-started, as well as fixes to content noticed while updating screenshots.

Figure titles added for images in getting-started and account management sections.

QA steps: ran linkcheck, edited with linter extensions, viewed rendered HTML.

This commit addresses task FFTK-3481, "Update Screenshots of UI"

PR Template and Checklist

Please complete as much as possible to speed up the reviewing process.

Readiness and adding reviewers as appropriate is required.

All PRs should be reviewed by a technical writer/documentation team and a peer.
If effecting customers—which is a majority of content changes—a member of Customer Success must also review.

Readiness

• Merge (pending reviews)

Checklist

• 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.

[vanmaegima]

@kprosise It seems like we didn't get the automated build on this PR? I only see the vale run.
As this brings a lot of new images, I would like to review the build html.

[vanmaegima]

This doesn't seem to match the old file.