Use GitLab SVG icons in file_type_icon_class helper

What does this MR do?

This MR replaces fontawesome icons in the file_type_icon_class helper with our GitLab SVGs. In particular, the following icons have changed:

• folder -> folder-o
• archive -> archive
• share -> share
• file-pdf-o -> document
• file-image-o -> doc-image
• file-archive-o -> doc-compressed
• file-audio-o -> volume-up
• file-video-o -> live-preview
• file-word-o -> doc-text
• file-excel-o -> document
• file-powerpoint-o -> doc-chart
• file-text-o -> doc-text

The file_type_icon_class helper is currently used by the following 2 helpers:

• tree_icon
• blob_icon

Those got updated as well by invoking the sprite_icon helper.

Screenshots

N/A

Does this MR meet the acceptance criteria?

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

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #246739 (closed)