[Feature] Scraping scene markers

[Maista6969]

Some sites and networks offer marker data for their scenes, most often through their API. Currently this can only be exploited by sceneByFragment script scrapers as they can use the Stash GQL API to query for extra information about the current scene and then subsequent mutations to add markers. This is not possible for URL scrapers since they do not receive any information about the scene they are scraping

I don't like the idea of marker scraping being limited to script scrapers, nor of scrapers needing to do this extra work for something that should be Stash's responsibility. The fact that this adds markers to a scene even before the user has reviewed the scrape results in the UI can also be unfortunate.

I think a scraper could return markers in the following format, with an example for the birthday party that starts at 2 minutes into the video:

{
  "name": "Birthday Party",
  "start": 120,
  "end": 155,
  "primaryTag": "Celebration",
  "secondaryTags": ["Cake", "Gay Ol' Time"]
}

When presenting this in the UI these markers could be shown in the same style as tags and the user could choose which ones they wanted to import exactly like tags behave today: the only thing that would be different is that markers have secondary tags and I can't think of a nice clean way to display that

[p0rnb0x]

stash also has no support for your "end" key ...

there's $400 bounty [#3147 -> #3530] but no progress yet on end time for markers