Update Playing Videos page for Godot 4.5

[berarma]

Removed another limitation: change playback speed.

Added Shutter Encoder as a FFmpeg GUI. Related to #10942.

I've decided to remove the date from the FFmpeg warning since they have already released a point version but without the fix. And I don't know how many more they will release yet. I hoped that the next major version was closer to being released.

Changed the GOP description a bit to hopefully better fit the rest of the documentation.

[skyace65]

What specifically in this PR only applies to 4.5?

[berarma]

What specifically in this PR only applies to 4.5?

I've removed some limitations. I've taken the opportunity to rework some of the text I did previously, and reference Shutter Encoder.

[skyace65]

Got it. This needs to be rebased since I just merged #10721. Also is there a reason this is marked as a draft?

[berarma]

Oh, sorry, I had forgot about that PR. There's another limitation to remove. I'll do it in this PR.

It's marked as a draft because one of the new features wasn't yet merged. Now that it is I'll update this PR.

The reason I've reworked some of my previous additions to this page is that I feel a bit insecure writing documentation. When I read some parts of it, it feels too verbose or more intricate than necessary. Your judgement on this would help me. Thanks.

[berarma]

Description updated.

[berarma]

After testing Shutter Encoder myself I've decided against including it in the docs because it uses the worst possible encoding parameters and offers no way to change them.

[skyace65]

Looks good! Only one minor change needs to be made.

[berarma]

I've moved the doc comment below the warning that it refers to so that it's more clear where it belongs. I've added the commit refs to the comment and a minor rewording of the warning.

[skyace65]

Thanks!