Refactor: Migrate Sass to be 2.0.0-friendly

[driskull]

Description

The latest dependency bump led to the following build warnings:

DEPRECATION WARNING: Using / for division is deprecated and will be removed in Dart Sass 2.0.0.

We should migrate our style files to be Sass 2.0.0 ready. The following are some changes that will be needed:

• use math.div instead of /
• use @use (and @forward) instead of @import

Proposed Advantages

Prevent moving to the latest dependencies when they move to Sass 2.0.0.

Relevant Info

Sass provides a migrating tool to help with this: https://sass-lang.com/documentation/cli/migrator

Dependencies that use Sass will likely also need to be updated (e.g., calcite-base).

[jcfranco]

I noticed that these are handled in the sass-module branch and have respective GH releases.

@paulcpederson @macandcheese Could we possibly publish to NPM as 2.0.0? If I understand correctly, the sass-module branch changes are specific to Sass 2.0.0 migration, so it wouldn't be too tricky for teams to make the switch and possibly move from the deprecated node-sass package to sass.

[paulcpederson]

@jcfranco are these the only changes required? https://github.com/Esri/calcite-base/pull/34/files

[jcfranco]

@paulcpederson I think these should be it: 8279f24~...3ced2eb

[paulcpederson]

Oh, right I remember this.

I think we could just merge these into master and publish them as 2.0.0.