[DOCS] Endpoint Management docs: consistency fixes, prerequisite callout

[joepeeples]

Description

Most of the pages for endpoint management (the Manage section in the side nav) are very similar, so they should have consistent docs. Over time, phrasing has been edited on a page-by-page or feature-by-feature basis, without maintaining consistency across all features.

Additionally, the @elastic/security-docs team discussed using a dedicated "Prerequisites" callout for noting user role requirements, so while we're taking a more global look at these pages, we can also add this box across all Manage pages.

Sample syntax:

.Title
*****
Text text 

* Bullet
* Bullet

Text text text 

*****

Acceptance Criteria

• Add Prerequisites callout box
• Rename "actions button" to "actions menu"
• Various tweaks to "View and manage x" sections (Probably use Blocklist as a model, since it's the most recently worked-on page)