* Removed package babel.config.js and pointed webpack to the root one

* Made base webpack config take a packagePath parameter and moved it to the monorepo root

* Added webpack prod/dev build configs for api-explorer and extension-api-explorer packages
- utilized by the 'package' script in the respective package.json files 
- Also removed superfluous --mode=production webpack cli argument. The mode option in the config file achieves the same.
- https://www.npmjs.com/package/webpack-merge

 - Maybe we can use this for extending/merging webpack configs.

* Extended and reused the root jest config in api-explorer and try-it packages
- This allows us to run just the api explorer package tests
- Additional arguments passed to the jest cmd were replaced by the `testMatch` property defined in the local jest config.
- Completely removing the jest config from api-explorer causes yarn to run all tests because the rootDir becomes the directory containing the config file and it uses the "testMatch" property defined in there.
- The same pattern can be followed in all other workspaces: 1) extend base jest config, 2) explicitly assign rootDir 3) define the testMatch property

* Addressed eslint config rule overrides
- The pre-commit hook seems to be working as intended now.

* Added a no-var-requires override for js files

* Cleaned up package.json from duplicates already existing in root package.json

* Sorted dependencies/devDependencies

Co-authored-by: John Kaster <johnk@looker.com>