Feature: Add button to video player that allows the user to search & add subtitles to the current Video

Start by reviewing the existing dul/feature/subtitle-search branch and the current video player, subtitle, settings, and movie or episode management entry points. Break the proposal into a scoped plan covering subtitle search, local storage, suggestions, administrator approval, merging, and the global setting; the work is done only when the agreed subset is implemented and verified across those flows.

Issue description

It would be a great feature to be able to add subtitles to a video on-the-fly for viewers. Of course, we want to prevent that a user downloads 50+ subtitles and that all of these also show up for every other viewer. Instead I suggest that the current viewer can download as many as he likes, and they get added into the browsers localstorage or local browser DB, but the viewer can then mark any of these local subtitles as "suggested". I would like to prevent the user from being able to just upload straight to our servers .. but maybe these suggestions could be viewed in the admin-interface alongside a video and the content-manager can then click on a button "add subtitle" which would auto-download from the API and append to the video, including a proper language label.
So the following things would have to be done to complete this task:

• add API for opensubtitles or similar, allow admin to add login-credentials in the settings page
• add "search for subtitle" button the video player, maybe in the subtitle dropdown
• add a popup for subtitle searching, with a string input for your query, a checkbox for comparing the video hash (if this even works?) and a language filter, and of course a "download & use" button or similar for the individual search results
• visually distinguish the "local" subtitles from the official streama subtitles, maybe with a little tag-like label next to the subtitle name
• load subtitle data into localstorage or browser-DB
• add button "suggest as official subtitle" which creates a subtitle-suggestion with all the required data for content-managers
• show subtitle-suggestions in the movie & episode management area
• add feature to download & add subtitle suggestions as content-managers
• for users that suggested subtitles that were later applied by content-managers, prevent that this subtitle shows up twice. so add some sort of merging-logic
• add new Checkbox in the settings page to globally add or remove this entire feature

Examples from VLC

Existing Branch

FYI, there is an existing branch where i started on this already. Not sure how much of this is usable:
https://github.com/streamaserver/streama/tree/dul/feature/subtitle-search