Incomplete Content-Security-Policy blocks video on "Set up Relays" page
Affected page: https://www.torproject.org/getinvolved/relays.html.en
Problem: "No video with supported format and MIME type found"
The video's URL is https://media.torproject.org/video/2012-03-04-BuildingBridges.ogv and forbidden by CSP.
Solution: Change
```
Content-Security-Policy: default-src 'self'; script-src 'self'; style-src 'self' 'unsafe-inline'
```
(https://www.hardenize.com/report/torproject.org/1544035352#www_csp)
to
```
Content-Security-Policy: default-src 'self'; style-src 'self' 'unsafe-inline'; media-src 'self' https://media.torproject.org
```
or even to
```
Content-Security-Policy: default-src 'self'; style-src 'self' 'unsafe-inline'; media-src 'self' https://media.torproject.org; frame-ancestors 'self'; block-all-mixed-content; disown-opener; plugin-types application/pdf; base-uri 'self'
```
**Trac**:
**Username**: darkspirit
issue