### What changes were proposed in this pull request?
This PR proposes to add linter for JavaScript source files.
[ESLint](https://eslint.org/) seems to be a popular linter for JavaScript so I choose it.
### Why are the changes needed?
Linter enables us to check style and keeps code clean.
### Does this PR introduce _any_ user-facing change?
No.
### How was this patch tested?
Manually run `dev/lint-js` (Node.js and npm are required).
In this PR, mainly indentation style is also fixed an linter passes.
Closes#32274 from sarutak/introduce-eslint.
Authored-by: Kousuke Saruta <sarutak@oss.nttdata.com>
Signed-off-by: Kousuke Saruta <sarutak@oss.nttdata.com>
