feat: include pre-built JS files that are browser-loadable and CDN-ready

when I would like to use the Hedera SDK in a browser application
but I'm required to use a Javascript build tool/ bundler before being able to use it in my application
when I'm simply trialling the SDK, or building a POC, I would prefer to simply import the entire SDK from a CDN URL

add an npm run script within this repo that builds/ bundles the SDK
its output should functional within a browser application
- e.g. in UMD format, compiled into a single file, and comes in "full" format as well as minified+source mapped format
place the output in a dist directory within the repo
add a CI/CD step that performs
- the npm run script which performs such a build upon each release
- syncs the built file onto CDNs such as jsdeliver

Refs