Refactor wix module to split into a separate Builder and Wix types

[volks73]

The Wix type in the wix module for the project is only partially implementing the Builder pattern, which makes it very verbose and confusing during development. It would be better to split the functionality into a Builder type, which focuses on configuration and a read-only Wix type that focuses on execution. Maybe the Wix type can be renamed to Executor?

Ideally, I would like to complete this refactoring before resolving too many of the recently added enhancements.

[volks73]

This has been partially completed as of 3c51aaf.

The initialization functionality has been split into Builder/Execution pattern but the remaining "modes", i.e. creation (default), sign, and print still need to be split into separate modules and the Builder/Execution pattern.

[volks73]

This is fully completed as of 7027baa.