Port physics interpolation docs from 3.6

[skyace65]

This is a copied and modified version of the physics interpolation docs from the 3.6 branch of the documentation. 2D physics interpolation exists in 4.3, however 3D interpolation only exists in 4.4 so this can't be cherry picked.

Changes I've made compared to the 3.6 version of these pages

• Changed "Camera" references to "Camera3D"
• Changed "Spatial" referenced to "Node3D"
• Changed multi-mesh method name to reflect 4.4 version of that method
• changed "phsyics fps" to "physics ticks per second"
• replaced reference to the method "set_as_toplevel" to the property "top_level". The method doesn't seem to exist anymore
• Re-did 2 editor images for 4.4, converted the other 2 to webp
• Applied suggestions from AThousandShips and LawnJelly in their review of PR Add physics interpolation docs to 4.3 #9738.
• Broke up lines of text so they're not extremely long.

[tetrapod00]

I'm not sure if it matters for rendering the page, but at least for consistency, we should use the order for header syntax that is standard in other pages:

Page title
==========

Header
------

Sub-header
~~~~~~~~~~

Sub-sub-header
^^^^^^^^^^^^^^

This page uses ^^^ for everything, so all those should use --- instead. And you should consider using subheaders with ~~~ for some of the headers below Cameras, since they're all meaningfully related. UNLESS you are intentionally trying to keep everything at the same header level so it shows up in the sidebar.

The other pages here need similar changes. If you want specific suggestions for exactly which header syntax to use for each I can make individual suggestions for them.

[tetrapod00]

This can also be done in a later PR without breaking translations, so feel free to ignore and defer this one

[skyace65]

I'll implement this, and change all the ^^^^ to ~~~~

[tetrapod00]

Suggested change

	Camera "target" Node, this transform will only focus the Camera on the target *at
	Camera "target" node, this transform will only focus the Camera on the target *at

"Node" usually not capitalized in most cases since its very common.
Honestly "Camera" may or may not need to be capitalized either thoughout this page, but that case is more subjective and I understand why it currently is capitalized.

[skyace65]

"Camera" was probably capitalized because that was what "Camera3D" was named in 3.x. I'll go through and change it as applicable.

[tetrapod00]

First batch of suggestions. I'll try to come back and look again after building this locally.

We could probably merge this as-is though, since it is pretty good already and already exists in the 3.6 docs. We definitely shouldn't delay this to after the release of 4.4

[skyace65]

I've applied changes based on tetrapod's review. The one section that used uppercase "Camera" everywhere is now using either "Camera3D" or "camera". I'd appreciate someone else looking it over to make sure everything flows right, it seems kinda weird to switch back and forth.

[skyace65]

Fixed

[mhilbrunner]

Thank you, great work! Merged.