refactor: remove baseUrl from all TSConfig files

Per the [official documentation](https://www.typescriptlang.org/tsconfig/#baseUrl):
> This feature was designed for use in conjunction with AMD module
loaders in the browser, and is not recommended in any other context.
As of TypeScript 4.1, baseUrl is no longer required to be set when using paths.

Author: haoqunjiang

template/tsconfig/base/tsconfig.app.json

@@ -6,7 +6,6 @@
     "composite": true,
     "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
 
-    "baseUrl": ".",
     "paths": {
       "@/*": ["./src/*"]
     }

template/tsconfig/nightwatch-ct/tsconfig.app.json

@@ -6,7 +6,6 @@
     "composite": true,
     "tsBuildInfoFile": "./node_modules/.tmp/tsconfig.app.tsbuildinfo",
 
-    "baseUrl": ".",
     "paths": {
       "@/*": ["./src/*"]
     }