Refresh dependencies, drop node-sass

`npm audit` revealed some vulnerabilities:

```

scss-tokenizer  <=0.4.2
Severity: high
Regular expression denial of service in scss-tokenizer - https://github.com/advisories/GHSA-7mwh-4pqv-wmr8
fix available via `npm audit fix --force`
Will install node-sass@4.5.3, which is a breaking change
node_modules/scss-tokenizer
  sass-graph  >=2.2.0
  Depends on vulnerable versions of scss-tokenizer
  node_modules/sass-graph
    node-sass  >=4.6.0
    Depends on vulnerable versions of sass-graph
    node_modules/node-sass

3 high severity vulnerabilities

```

We don't need node-sass, and sass-loader is just as happy using
another sass implementation. The preferred one is dart-sass which
is simply called sass in npm.

In the process, I also did an `npm update` just for good measure.

js/src/bootstrap.scss

@@ -1,14 +1,12 @@
-/*!
- * Bootstrap v5.1.3 (https://getbootstrap.com/)
- * Copyright 2011-2021 The Bootstrap Authors
- * Copyright 2011-2021 Twitter, Inc.
- * Licensed under MIT (https://github.com/twbs/bootstrap/blob/main/LICENSE)
- */
+@import "mixins/banner";
+@include bsBanner("");
+
 
 // scss-docs-start import-stack
 // Configuration
 @import "functions";
 @import "variables";
+@import "maps";
 @import "mixins";
 @import "utilities";