Avoid blowing up user code when `$user:$password` string is longer than
127 bytes. Use String to both manage the memory and handle concatenation.
Also clean-up historical quicks such as
- `if(StringObject)` that is always true since we implemented SSO
- `authReq = "";` / `authReq = String();`, which will happen anyway
- `(String)...` casts that happen anyway, implicitly (and which is also not a 'cast' btw, we do init it)
1a49a0449b