WIP: Implement new Fan-In/Out/General

[w31t1]

This PR replace the old Fan-In/Out/General-Out metric by a new approach used in my projects.

The current code is partially not working (see #250, #358) still Work in Progress as I discovered in #102. I already state that the current calculation depends on the ordering of the input files.

The new calculation is as described in lizard_ext/lizardio.py:

        Runs the Lizard Extension for calculation of fan-in and fan-out
        metric in the source code.

        Currently supported languages:
            - CLike:
                - Fan-In:          The count of functions this function is called.
                - Fan-Out:         The count of function called in this function.
                - General Fan-Out: The count of functions called in this function.
            - Python
                - Fan-In:          The count of functions this function is called.
                - Fan-Out:         The count of functions called in this function.
                - General Fan-Out: The count of different functions called in this function.

        Metric definition:
            Fan-In:          The grade of units/entities dependent on this code part inside the unit.
            Fan-Out:         The grade of units/entities this code part depends on.
            General Fan-Out: A more general grade of units/entities this code part depends on.

        Limitation:
            - Metric definition depends on language: Functional languages this metric is different
              calculated than object-oriented languages (because of language design).
            - Metric calculation depends on reader extension: Only CodeReader with implemented
              function `external_dependencies` are used to calculate the fan-out metric.
            - Exact metric calculation depends on not-existent knowledge: Programming languages can
              own a lot of features which are not known at calculation time, e.g.:
                - defines/templates (C/C++)
                - compiler/interpreter introduced hidden function calls (SPARC, x86, PowerPC)
                - different language versions (python {2.7/3.11/...}, **C{99/11/..}**

The following tasks are not fulfilled:

1. Fix unit tests, add additional validation tests

This PR is a RFC (Request for Comments). The development is still ongoing, tests will be added for C and Python.

@terryyin : Are you interested in this change?
@mehrdad89 : Do you still want to implement your approach?

It is also a question, if it is better to create a new extension file than canibalize this one.

[terryyin]

If you like it you should have put some tests on it.