Add aria-label for links on project, commit and projects import

What does this MR do and why?

Add aria-label for links on project, commit and projects import

Improving accessibility of those links

Covering issues: 1954161, 1935131, 1954352, 1934241, 1928432

References

Please include cross links to any resources that are relevant to this MR. This will give reviewers and future readers helpful context to give an efficient review of the changes introduced.

• #517665 (closed)

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

How to set up and validate locally

Visit the target page and manually verify the arial-label is applied correct.

Pages:

• Commits page for a project (the tag pill on the right side of the commit)
• New Project > Import (you might want to manually adjust the if statement in app/views/projects/new.html.haml to see the import_project_pane partial) (the "Learn more" link in the alert)
• Dashboard > Projects (the link surrounding each project's avatar)

Related to #517665 (closed)