feat(context): Add decorator factories

The feature implements common behavior for decorator functions
for classes, methods, parameters, and properties. It takes
inheritance into consideration and aggregate metadata for properties,
methods, and parameters into one object by type per class.

It also allows control for decorator inheritance by setting the
`allowInheritance` flag or overriding `inherit()`.

Author: Raymond Feng

packages/context/package.json

@@ -22,12 +22,16 @@
   "author": "IBM",
   "license": "MIT",
   "dependencies": {
+    "debug": "^3.1.0",
+    "lodash": "^4.17.4",
     "reflect-metadata": "^0.1.10"
   },
   "devDependencies": {
     "@loopback/build": "^4.0.0-alpha.7",
     "@loopback/testlab": "^4.0.0-alpha.16",
     "@types/bluebird": "^3.5.18",
+    "@types/debug": "0.0.30",
+    "@types/lodash": "^4.14.87",
     "bluebird": "^3.5.0"
   },
   "keywords": [