i18n linters - ESLint JS

Part of https://gitlab.com/gitlab-org/manage/issues/20

We can lint for unwrapped strings (in simple/common cases) in JS files using ESLint. Note: This is for .js files only. Vue file linting is tracked in https://gitlab.com/gitlab-org/gitlab-ce/issues/57969.

  • We should autofix as many cases using the linter as we can and this should be split across many MRs to allow for easy manual review.

  • We should use danger to enforce externalization in the changes of a branch going forward. We should add the linter to the codebase. The linting will be enforced during the static analysis job which runs via the CI pipeline.

  • We should generate a list of cases that can't be autofixed to be worked through manually or to have autofix functionality written for them.

Edited by Brandon Labuschagne