Search Box to search for courses, streams and subtitles

[SebiWrn]

Motivation and Context

This Change solves the problem of finding lectures in a large list of lectures. It also enhances the search for subtitles or streams in courses.
Closes #1337.

Description

The change adds a search bar at the top of every page where you can search for courses or contents of a course, depending if you're on a course page or on the home page.

Steps for Testing

You can't test this change on the Testserver system.

You have to set up your own local instance of TUM-Live for testing and also have to setup your own meilisearch service.
To start the meilisearch service, you can run the following command:

docker run -it --rm \
    -p 7700:7700 \
    -e MEILI_MASTER_KEY='MASTER_KEY'\
    -v $(pwd)/meili_data:/meili_data \
    getmeili/meilisearch:v1.9 \
    meilisearch --env="development"

If the data isn't automatically exported to meilisearch, you can run this job from the Maintenance Tab in the Admin panel.

You can enter your search query in the search bar on every page or you can press 'Enter' while the search bar is focused to see the full search page with filters etc.

[CommanderStorm]

Hi, you were likely not expecting a review from me, but @joschahenningsen told me that meilisearch is happening and I thought that looking over the usage might be benefitial.

This is an incredibly large PR.
Reviewing this is impossible, anybody who tells you that they reviewed it is likely lying on at least some part.

=> Please in the future split your PRs way before the +2,513 lines mark.

[CommanderStorm]

From my point of view, there is nothing left to review.
There are a few threads (like #1380 (comment)) which are not quite resolved, but from my point nothing blocks merging.

[karjo24]

From my point of view, there is nothing left to review.

@CommanderStorm Thanks for your review and suggestions, it was much appreciated! :)