[UX] For icon browser, have option to filter by category of icons

[swampopus]

Description of the need

Similar to issue #7145, the volume of icons makes it difficult to find what I need. If the icons could be grouped into categories (eg, "Arrows", "Travel", "Tools", etc) that would make it much faster.

Proposed solution

In an ideal world, each icon is able to declare its category (or multiple categories). These would appear as a select list on the Icon Browser page, and, when selected, only those icons in that category would appear.

Draft of feature description for Press Release (1 paragraph at most)

Backdrop now allows the user to filter the icon browser by category of icon.

[swampopus]

I notice on the Phosphoricons.com site, each icon there already has "tags" associated with it. If that is data available to Backdrop, then I suggest that be used.

EDIT:

Okay, so Phosphoricons has a .ts file with all of its icons' information, including JSON arrays of tags:
https://github.com/phosphor-icons/core/blob/main/src/icons.ts

For example:

{
    name: "airplane",
    pascal_name: "Airplane",
    categories: [IconCategory.MAP, IconCategory.OBJECTS],
    figma_category: FigmaCategory.MAP,
    tags: [
      "vehicles",
      "airports",
      "flights",
      "flying",
      "planes",
      "transit",
      "transportation",
      "traveling",
    ],
    codepoint: 57346,
    published_in: 1.0,
    updated_in: 1.0,
  },

Would it be possible to include this file with Backdrop (in the /core/misc/icons directory)? It is 487 KB in size. It does contain just a little extra code besides the JSON, which would have to be preg_replace'd out before converting the JSON to an array that Backdrop can use.

This could also be something that Backdrop lets the end user do on demand, rather than package it with core. Or, it could just be in its own module, but I know that kind of defeats the point of merging the original Icon Browser module into core in the first place.