The new sip build system complies with pep 517 and
requires configuration by a standard pyproject.toml
file rather than running a single command. Along with
these changes the fixed sip.h file has been removed in
favour of a header generated locally if required.

We now support both the sip build systems as this is
required in our current support for multiple OSes. In
the process of adding support some cleanup has been
included:
  - the .sip files in our tree are now full module defs
    rather than the boilerplate being filled in by CMake,
    giving each module more flexibility.
  - the sipwrapper file has been removed in favour of a
    simpler script to simply strip the problematic code
    for C++17 compatability.

Removes all of the from __future__ imports that open and close the
brackets on the same line. This is most of them.

Also updated class_maker.py

Generate _commonqt4 sip for backwards compat

Refs #24827

Refs #24669

Import qtpy instead of PyQt4

use load_ui instead of genereated python ui files

Refs #24669

Add SANS v2 GUI to workbench interfaces

Begin to change SANS code to use qtpy

Begin to change SANS import to mantidqt from mantidqtpython

Refs #24669