Compiling for Linux: Outdated information for Alpine Linux, reference to invalid `libexecinfo-dev` package

**Your Godot version:** 4.2.1

**Issue description:** Alpine packages in 'Compiling for Linux' section no loner valid

**URL to the documentation page:** https://docs.godotengine.org/en/stable/contributing/development/compiling/compiling_for_linuxbsd.html

Alpine Linux uses `musl` rather than `glibc`. The instructions for required packages in Alpine Linux include `libexecinfo-dev`, which has not been available on Alpine Linux since 3.17.

See also [`musl` support issue](https://github.com/godotengine/godot/issues/20037). The reference to `libexecinfo-dev` should be removed from the docs, with a note to use the `execinfo=no` option when compiling with `musl`.