Move `zowed` folder into `native/c`

[traeok]

Is your feature or enhancement request related to a problem or limitation? Please describe

When we were using Go for the middleware, it made sense to keep the middleware code separate from the backend.
But now that we use the same language for both layers, and we re-use code in the native/c folder, it would be better organized under a single c folder. This is especially true now that we have tests for zowed in the native/c/test folder, which feels a bit fragmented.

Describe your enhancement idea

Move the zowed folder into native/c and make necessary code & makefile changes to get the middleware to build & run successfully

Describe alternatives you've considered

We can keep as-is and move the tests into the native/zowed folder