Changes package namespace

[ebresie]

Presently much of the codebase is based on initial defined "org.apache.netbeans.modules.python4nb" package. Since this is not specifically part of the Apache organization and is an independent plugin, changing this to more appropriate package namespace is needed.

To align with GitHub project location, name to refactor to use "io.github.ebresie.python4nb" which will further link up to the GitHub page
https://ebresie.github.io/python4nb/

[ebresie]

It may be if want to make it more than a one-person project, then a full domain name will need to be register at which point another rename may be necessary.

[ebresie]

Need to ensure places with paths like org/apache/netbeans/modules/python4nb/editor/ are also updated