- release date fixed typing

- improved test, custom tests panel typings to accept proper types (custom test panel can accept custom tests and custom project custo tests but not normal tests)
- load full test protocol is working for normal, custom and submit tests in the do exercise editor
- changed module system to commonjs
  - because we now use typescript 3.8 (for some more utility funcs) which requires a new tslib version and webpack threw error export '__spreadArrays' was not found in 'tslib'
  - so all imports have been changed to not use esnext syntax (import x from ...)
  - this might have increaded bundle size because lodash and moment are now fully bundled?

- moved all dev dependencies into proper package.json section
- editor now uses the programming languages from backend and imports dynamically the syntax highlight file
- markdown fenced code blocks now loads dynamically the syntax highlight file

- added json escaped editor for regex tests (exercise editor)

- left time is now displayed on the do exercise site
  - if left time <= 0 do exercise site is readonly
- open exercises displays left time