Support Next.js folder naming patterns

[ziyafenn]

Housekeeping

• I'm sure this issue is not a duplicate

Information:

Next.js with new app router has it's own folder naming conventions/patterns that currently are unsupported by vscode-icons.

Doing it via Fine Tuning is currently not possible as it doesn't accept RegEX, plus it would be a nice future similar to current Angular and NestJS support.

As an example:

Dynamic Routes: [folder] | [...folder] | [[...folder]]
Route Group: (folder)
Private Folder: _folder

Here is the full list of folder/file naming conventions: https://nextjs.org/docs/getting-started/project-structure#top-level-folders.