feat(ionic): update tsconfig.json (#224)

The current tsconfig doesn't extends the base tsconfig, consequently it is impossible to imports items from the generated libs using the lib path alias generated by NX.
See here the original NX file: https://github.com/nrwl/nx/blob/master/packages/angular/src/schematics/application/files/tsconfig.json

packages/ionic-angular/src/schematics/application/_files/tsconfig.json

@@ -1,18 +1,16 @@
 {
-  "compileOnSave": false,
+  "extends": "<%= offsetFromRoot %>tsconfig.base.json",
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.app.json"
+    },
+    {
+      "path": "./tsconfig.spec.json"
+    }]
+  ],
   "compilerOptions": {
-    "outDir": "./dist/out-tsc",
-    "sourceMap": true,
-    "declaration": false,
-    "module": "esnext",
-    "moduleResolution": "node",
-    "emitDecoratorMetadata": true,
-    "experimentalDecorators": true,
-    "importHelpers": true,
-    "target": "es2015",
-    "typeRoots": ["./node_modules/@types"],
-    "lib": ["es2018", "dom"],
-    "baseUrl": "./",
     "paths": {
       "@<%= npmScope %>/*": ["<%= pathOffset %>libs/*"],
       "@<%= npmScope %>/ionic": [