[wct] Use gts for linting and formatting

[koshilki]

• Use gts instead of tslint+clang-format
• Lint using NPM scripts instead of gulp
• Fix formatting according to gts rules
• Fix gts lint rules violations
• Refactor clireporter status colorise method

Fixes #224

Co-authored-by: @merlinnot

[googlebot]

We found a Contributor License Agreement for you (the sender of this pull request), but were unable to determine that you authored the commits in this PR. Maybe you used a different email address in the git commits than was used to sign the CLA? If someone else authored these commits, then please add them to this pull request and have them confirm that they're okay with them being contributed to Google. If there are co-authors, make sure they're formatted properly.
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[koshilki]

@merlinnot FYI

[merlinnot]

I'm ok with my work being contributed to Google.

[koshilki]

@googlebot CLA issue should be fixed by now

[merlinnot]

LGTM once we merge koshilki/tools#1

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed after being marked stale. If you're still facing this problem with the above solution, please comment and we'll reopen!