Migrate from tslint (unsupported) to ESLint

[omkar-ethz]

Migrate from TSLint (deprecated) to ESLint following this guide. ng lint now runs and reports some errors and warnings. Also shown while editing in VSCode.

Current output of ng lint (last few lines):

✖ 85 problems (48 errors, 37 warnings)
  4 errors and 0 warnings potentially fixable with the `--fix` option.

Lint warnings found in the listed files.

Lint errors found in the listed files.

[minottic]

super minor comment. thanks for the change

[minottic]

missing newline?

[omkar-ethz]

Thanks, fixed!