🔥 Removed v0.1 controllers & routes (#11103)

no issue 

- Removed v0.1 controllers
- Removed 0.1 API unit tests
- Removed 0.1 API app and mount point
- Removed leftover use of v0.1 in entry-lookup test suite
- Removed frontend client API enpoints and related code (middleware)
- Fixed prev/next test suites to use v2 API
- Set default API version to explicit v2 in UrlUtils
- Removed v0.1 API regex from public files middleware

core/server/api/index.js

@@ -1,5 +1,4 @@
-module.exports = require('./v0.1');
-module.exports['v0.1'] = require('./v0.1');
+module.exports = require('./v2');
 module.exports.v2 = require('./v2');
 module.exports.canary = require('./canary');
 module.exports.v3 = require('./canary');