Migrating (trying to) but there is an error with I don't know what to do.
There are no commands defined in the "migrate" namespace.
This error goes away when the data migration tool is installed using composer.
I debugged bit deeper into this error and found that the module's code of adding its shell commands are not working correctly. I didn't spend time to correct it instead installed the data migration tool using composer and it worked!
And, just in case, if you get Wrong Credential message when installing the tool using composer, you need to type the private key in the password field. The normal pasting password function(on right click) didn't seem to work here. This made me choose to install the tool manually, LOL.