release_v20230722_0

Libcaliptra (#496)

* libcaliptra

Derived from the api example in hw-model/c-binding/examples/api, this
is the initial skeleton of a more generic client API for Caliptra,
intended to abstract away the details of the implementation.

Client applications will include caliptra_api.h and implementations
will provide definitions to the functions declared in caliptra_if.h,
check the README.md for more information.

* Add support for integration with the model

This adds a generic reference to demonstrate client application use of the
Caliptra C API, and an example implementation of an interface, in this case
connecting the generic reference application to the hardware model.

Build happens from within the examples/hwmodel/ directory. Run `make` and then
run `./hwmodel` to execute the example.

This also removes the more basic if_test directory as it is now redundant