refactor(cli): activate strict mode in TS (except strictNullChecks)

Activating `strictNullChecks` makes TS compilation throw a lot of errors that need to refactor some part of the code.
These refactoring will be done in another commit.

lib/cli/tsconfig.json

@@ -2,7 +2,9 @@
   "extends": "../../tsconfig.json",
   "compilerOptions": {
     "rootDir": "./src",
-    "types": ["node", "jest"]
+    "types": ["node", "jest"],
+    "strict": false,
+    "strictNullChecks": false
   },
   "include": ["src/**/*"],
   "exclude": ["src/**/template*"]