[WIP] Update config to implement a single entry point (index.js)

[hutch78]

This PR is attempting to bring a single entry-point back to this SDK instead of having to import from /browser and /node

Currently, this update has errors when run in node:

import BoxCastSDK from "@boxcast/boxcast-sdk-js";

Error: unable to locate global object
    at /Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:12463
    at Object.300 (/Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:12507)
    at r (/Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:48718)
    at Object.614 (/Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:48588)
    at r (/Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:48718)
    at /Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:48994
    at /Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:49002
    at /Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:81
    at Object.<anonymous> (/Users/hutch-boxcast/Dev/boxcast-sdk-js/dist/index.js:2:214)
    at Module._compile (internal/modules/cjs/loader.js:1085:14)

and when trying to build:

npm run build:prod

[webpack-cli] Error: Universal Chunk Loading is not implemented yet
    at EnableChunkLoadingPlugin.apply (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/javascript/EnableChunkLoadingPlugin.js:104:12)
    at WebpackOptionsApply.process (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/WebpackOptionsApply.js:147:40)
    at createCompiler (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/webpack.js:76:28)
    at create (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/webpack.js:113:15)
    at webpack (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/webpack.js:121:46)
    at f (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack/lib/index.js:37:15)
    at WebpackCLI.createCompiler (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack-cli/lib/webpack-cli.js:1337:24)
    at async WebpackCLI.bundleCommand (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack-cli/lib/webpack-cli.js:1433:20)
    at async Command.<anonymous> (/Users/hutch-boxcast/Dev/boxcast-sdk-js/node_modules/webpack-cli/lib/webpack-cli.js:384:25)
    at async Promise.all (index 1)