annotated sentences - source indication

[uklomp]

Hi @Jetske
When we edit or upload an annotated sentence, I'd like to have several boxes with several sources we're working with, that we can tick, and that yield different results. I'm envisioning the following changes:

'Corpus' should be 'Source'
During uploading or editing, the following sources should be able for us to select / tick:

• Corpus NGT
• Samenwerking TYD en ZinInNGT
  And maybe more options should be available in the future.

When Corpus NGT is ticked, the following should be visible on the website:
Source
Corpus NGT (O. Crasborn, I. Zwitserlood, J. Ros & M. van Zuilen (2020)), [link to corpus video]

We will provide the link to the corpus video, manually for now :( - but it would be nice if it's clickable, that's not the case right now. And it would be nice if the reference appears automatically.

When the other options are ticked, I'm not sure yet which text needs to appear, but probably it will be simpeler and just the mentioning of the source.