Sync with Raccoongang

[dyudyunov]

Change description

• Add translations support.
• Remove brightcove.css to fix player control buttons duplication.
• Minor fixes according to relocation to py3

Type of change

• [x] Bug fix (fixes an issue)
• [x] New feature (adds functionality)

Related issues

Checklists

Development

• [ ] Lint rules pass locally
• [ ] Application changes have been tested thoroughly
• [x] Automated tests covering modified code pass

Security

• [ ] Security impact of change has been considered
• [ ] Code follows company security practices and guidelines

Code review

• [ ] Pull request has a descriptive title and context useful to a reviewer. Screenshots or screencasts are attached as necessary
• [ ] "Ready for review" label attached and reviewers assigned
• [ ] Changes have been reviewed by at least one other contributor
• [ ] Pull request linked to task tracker where applicable

[bryanlandia]

Thank you for the PR. I'll take a look next week