feat(GlSafeHtmlDirective): Add directive to sanitize html

Please don't merge this MR until gitlab!31928 (comment 347466020) [LICENCE Approval] get resolved

What does this MR do?

This adds a new directive GlSafeHtmlDirective which allows you to sanitize html in Vue

• It is basically a safer (secure) version of v-html
• The provided HTML is passed to dompurify available HTML sanitizer before it's interpreted.

Screenshot & Documentation

• Storybook - live demo

• Storybook - Documentation

Note

✅ (Not required now)

Adds a new dependency dompurify (v2.0.11, "MPL-2.0 OR Apache-2.0"), and it should be good as per this.

Also, there is an MR in Gitlab which is going to add the same dependency - gitlab!31928 (merged)

Does this MR meet the acceptance criteria?

Conformity

• Code review guidelines.
• GitLab UI's contributing guidlines.
• If it changes a Pajamas-compliant component's look & feel, the MR has been reviewed by a UX designer.
• If it changes GitLab UI's documentation guidelines, the MR has been reviewed by a Technical Writer.
• If the MR changes a component's API, integration MR(s) have been opened in the following projects to ensure that the @gitlab/ui package can be upgraded quickly after the changes are released:
  • GitLab: mr_url
  • Customers Portal: mr_url
  • Status Page: mr_url
• Added the ~"component:*" label(s) if applicable.

Closes #822 (closed)