Resolve "Problem with prettier setting trailingComma: all"

This MR:

• applies trailingComma: "es5" to all node scripts and trailingComma: "all" to all babel-transformed scripts so that we do not break compatibility with node 6 and 7.
• removes node scripts from .prettierignore so that they get the benefits of prettier as well
• adds /app/assets/javascripts/locales/**/app.js to .prettierignore (suggested in https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/17907#note_64748553 – thanks @leipert 😄)
• adds /scripts/ to .eslintignore and removes unnecessary /* eslint */ rule overrides in those files.
• prettifys all node scripts and config files

Closes #44589 (closed)