Replace double angle icons with chevron

What does this MR do?

Remaps angle- icons to chevron- icons. In gitlab-design#704 (closed) the effort started to clean up and align icon naming, part of that was standardizing on chevrons instead of angles.

Currently, in the SVG library both angles and chevrons exist, each with an identical counterpart. After updating to the chevron naming, the angle icons will be deprecated from the SVG library.

In some instances the update replaces FontAwesome icons with GitLab SVGs. The right sidebar is out of scope here since it involves larger template and JS changes.

Replace instances of:

• angle-double-left with chevron-double-lg-left (includes related CSS classes)
• angle-double-right with chevron-double-lg-right (includes related CSS classes)

Location	Before	After
Wiki page
Wiki history
Wiki edit
Wiki clone
Wiki clone
Milestone instance
Issuable
Merge request

Conformity

• Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

N/A

Security

N/A

Relates to #222907 (closed)