Move FlorisModel realted utilities onto FlorisModel class

[bayc]

Feature or improvement description
This PR moves the FlorisModel utilities get_param, set_param, and print_dict onto the FlorisModel class and out of floris_model_utils.py.

This PR also organizes the methods on FlorisModel by functionality to make it easier to navigate for the developer. Let me know if you don't agree with this and I can remove the commit. If the reorganization if too much to view in the files changed along with moving the utility functions, you can see more localized changes with each of the commits.

Related issue, if one exists
None.

Impacted areas of the software
floris_model.py
floris_model_utils.py
tests

Additional supporting information
I also updated the tests to use the relevant methods, and moves the tests to floris_model_integration_test.py as well as utilities_unit_test.py. I am not 100% sure that the test_get_and_set_param test is a true integration test or more of a unit test, but seemed to fit well in the floris_model_integration_test.py file.

Test results, if applicable
Tests are passing.

[paulf81]

This looks really great @bayc thank you! I'm going to merge in now