Remove community health files from this repository

They've been moved to the @godotengine organization's .github
repository, which works as a fallback for all repositories in the
organization. This way, the Sponsor button is automatically displayed
on all repositories.

This closes #40972.

(cherry picked from commit f516dc11984b7de86c3a6024f52a4670d40a985c)

.github/FUNDING.yml

@@ -1,2 +0,0 @@
-patreon: godotengine
-custom: https://godotengine.org/donate

CODE_OF_CONDUCT.md

@@ -1,4 +0,0 @@
-# Code of Conduct
-
-By participating in this repository, you agree to abide by the
-[Godot Engine Code of Conduct](https://godotengine.org/code-of-conduct).