Clarify fioctl PKI ca create command

[kprosise]

Added sentence stating what is created. Minor cleanup, and moved the how-to content above the terminology section.

QA: Checked rendered HTML, no issues.

This commit addresses issue FFTK-1469, "… clarify that the fioctl command creates…"

PR Template and Checklist

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Overview

Why merge this PR? What does it solve?

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.
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Comments

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