Update prettier config and style repo accordingly

[gsong]

• build: standardize on 2 space indentation
• style: format according to prettier rules 💅

I think it's much more common in the JS/TS community to have 2 space indentations.

[gsong]

@microsoft-github-policy-service agree company="Sahaj Software"

[dayland]

Need deep review

[gsong]

Need deep review

FWIW, this is what I did:

1. Updated app/frontend/.prettierrc.json to remove tabWidth: 4 setting
2. Ran prettier --write . from the root of the monorepo to make sure all files comply to prettier settings, this will prevent future updates to files from adding unnecessary diffs.

Perhaps .vscode/ should be prettier ignored?