ONOS-7330 Added ONOS-P4 VM build script

Builds and OVA from scratch with the most updated tools in one command.
The build process is based on Vagrant.

Change-Id: I633d99092946f99e877f0c97631a4f99c5b1f37e
diff --git a/tools/dev/p4vm/.gitignore b/tools/dev/p4vm/.gitignore
new file mode 100644
index 0000000..c67d4b1
--- /dev/null
+++ b/tools/dev/p4vm/.gitignore
@@ -0,0 +1,2 @@
+.vagrant
+*.ova