Support transcript captions with line breaks

According to most captioning guidelines, a single line of text in a caption should generally be no more than 30-35 characters. Most recommendations aim for a maximum of 1-2 lines per caption, ensuring readability and comfortable fit within the screen space.

This is not currently supported in Aviary. Each transcript segment does not contain any line breaks and any line breaks included in a transcript import are normally ignored by Aviary.

1. Allow a user to import a VTT or SRT caption into Aviary and display the precise number of lines and characters as created in the imported file.
   

2. Provide a caption creator/editor that supports the creation of captions as distinct from transcripts.