Fix broken embedded video link in story panel

[mwu2018]

A user is able to create a story with embedded video. However, when the story is loaded, the video part is dropped.

Related issue https://github.com/TerriaJS/vic-digital-twin/issues/541.

[nf-s]

From discussion today

• Happy with Mike's current approach of checking iframes in story body
• There is a hard-coded list of allowed URLS (eg YouTube and Vimeo)
  • We will avoid adding to configuration, as it may allow use of #configUrl to change allowed URLs
• If any iframes exist in the story with URL that is not allowed - all iframes are removed
• This approach will work with Story Editor "Media" button

[nf-s]

• Add youtube "no-cookies" domain
• Add vimeo domain