Move hex cache (#291)

* hexcache is no longer generated at repo root, so remove it from package.json

* Modified templates to depend on local packages

* Adding bluetooth template for offline HEX cache

* Fix wrong package name in dependencies of bluetooth template

* Change package versions to * in templates

libs/templates/bluetoothprj/pxt.json

@@ -0,0 +1,13 @@
+{
+    "name": "{0} block",
+    "dependencies": {
+        "core": "*",
+        "bluetooth": "*"
+    },
+    "description": "",
+    "files": [
+        "main.blocks",
+        "main.ts",
+        "README.md"
+    ]
+}