build: read VM CPUs/RAM from builder/Vagrantfile

makebuildserver.config.py is no more, builder/Vagrantfile is now where the
CPU and memory is configured for the buildserver VM.  In fact, that was
always the actual place, the makebuildserver.config.py thing was just
confused.

This should have been part of !1222

fdroidserver/build.py

@@ -1277,8 +1277,7 @@ def main():
                     if m:
                         status_output['hostProcMeminfoMemTotal'] = m.group(1)
                         break
-        fdroid_path = os.path.realpath(os.path.join(os.path.dirname(__file__), '..'))
-        buildserver_config = os.path.join(fdroid_path, 'makebuildserver.config.py')
+        buildserver_config = 'builder/Vagrantfile'
         if os.path.isfile(buildserver_config) and os.access(buildserver_config, os.R_OK):
             with open(buildserver_config) as configfile:
                 for line in configfile:

tests/builder/Vagrantfile

@@ -0,0 +1,12 @@
+# generated file, do not change.
+# https://gitlab.com/fdroid/fdroid-bootstrap-buildserver/-/blob/c0762bf9398d0/provision.yml#L552
+
+Vagrant.configure("2") do |config|
+  config.vm.box = "buildserver"
+  config.vm.synced_folder ".", "/vagrant", disabled: true
+
+  config.vm.provider :libvirt do |libvirt|
+    libvirt.cpus = 24
+    libvirt.memory = 30720
+  end
+end