Ports: Add a cmake port

Yes, you build this *inside* serenity.

Ports/cmake/package.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env -S bash ../.port_include.sh
+port=cmake
+version=3.19.4
+useconfigure=false
+files="https://github.com/Kitware/CMake/releases/download/v$version/cmake-$version.tar.gz cmake-$version.tar.gz"
+depends="bash gcc make sed"
+
+port_path=$(realpath $(dirname ${BASH_SOURCE[0]}))
+
+build() {
+    return
+}
+
+install() {
+    cmake_dir="${SERENITY_ROOT}/Build/Root/home/anon/Source/cmake"
+    run rm -rf "$cmake_dir"
+    run mkdir -p "$cmake_dir"
+    run cp -r . "$cmake_dir"
+}
+
+post_install() {
+    echo +===================================================================
+    echo "| Successfully prepared the sources for cmake v$version!"
+    echo "| The other half of the install has to be done inside serenity"
+    echo "| to continue, re-image and run the vm, then do the following:"
+    echo '| '
+    echo '| $ cd Source/cmake'
+    echo '| $ ./bootstrap'
+    echo '| $ make && make install'
+    echo '| '
+    echo "| (These instructions are also available in $port_path/howto.md)"
+    echo +===================================================================
+}