This PR adds a configuration option to control the preloading of video data on
page load with the HTML5 'preload'[1] attribute on the `<video>` element.
The option is enabled by default, meaning that the `preload` attribute's value
will be 'auto'. If users want to prevent preloading of video data, they
can disable the option, which will set the attribute value to 'none'.
[1](https://www.w3schools.com/tags/att_video_preload.asp)
Closes issue 4110
Fix#4110 by adding an option to control the preloading of video data on
page load. If disabled ("false"), the browser will not preload any video
data until the user explicitly hits the "Play" button.
If enabled ("true"), the default behavior will be used, which means the
browser decides how much of the video will be preloaded.
The Caption object does not actually store any text lines for the
subtitles. Instead it stores the metadata needed to display and fetch
the actual captions from the YT timedtext API.
Therefore it may be wiser to rename the struct to be more reflective of
its current usage as well as the future usage once the current caption
retrival system is replaced via InnerTube's transcript API
