rename electroncash packages to electrumabc

[PiRK]

This will reduce the number of problems for developers and power users installing both electroncash and electrumabc as a library with pip install .

It opens the way for electrumabc to be used as a library, not just as a packaged application.

This was not done earlier because it is an invasive change that can potentially affect the build scripts and various tools in unexpected ways, but it has to be done sooner or later.

[PiRK]

It almost works, but there is a mysterious issue in the MacOS build script:

26470 INFO: checking EXE
26470 INFO: Building EXE because EXE-00.toc is non existent
26470 INFO: Building EXE from EXE-00.toc
26470 INFO: Appending archive to EXE /private/var/folders/wh/z5_y2cv53sg24tzvtw_f_y1m0000gn/T/cirrus-ci-build/build/osx/ElectrumABC
26483 INFO: Fixing EXE for code signing /private/var/folders/wh/z5_y2cv53sg24tzvtw_f_y1m0000gn/T/cirrus-ci-build/build/osx/ElectrumABC
26486 INFO: Building EXE from EXE-00.toc completed successfully.
26488 INFO: checking BUNDLE
26488 INFO: Building BUNDLE because BUNDLE-00.toc is non existent
26488 INFO: Building BUNDLE BUNDLE-00.toc
Removing qtweb qt3d qtgame qtdesigner qtquick qtlocation qttest qtxml qtqml qtsql qtserialport qtsensors qtpositioning qtnfc qthelp qtbluetooth pyqt5/qt/qml pyqt5/qt/plugins/position pyqt5/qt/plugins/sqldrivers libqsqlmysql.dylib libdeclarative_multimedia.dylib libqtquickscene2dplugin.dylib libqtquickscene3dplugin.dylib libqtquickcontrols2imaginestyleplugin.dylib libqwebgl.dylib libqtquickextrasflatplugin.dylib ibqtcanvas3d.dylib libqtquickcontrolsplugin.dylib libqtquicktemplates2plugin.dylib libqtlabsplatformplugin.dylib libdeclarative_sensors.dylib libdeclarative_location.dylib
----> Removed: ('PyQt5/Qt/plugins/platforms/libqwebgl.dylib', '/Users/admin/Library/Python/3.8/lib/python/site-packages/PyQt5/Qt/plugins/platforms/libqwebgl.dylib', 'BINARY')
----> Removed: ('QtWebSockets', '/Users/admin/Library/Python/3.8/lib/python/site-packages/PyQt5/Qt/lib/QtWebSockets.framework/Versions/5/QtWebSockets', 'BINARY')
----> Removed: ('QtQuick', '/Users/admin/Library/Python/3.8/lib/python/site-packages/PyQt5/Qt/lib/QtQuick.framework/Versions/5/QtQuick', 'BINARY')
----> Removed: ('QtQmlModels', '/Users/admin/Library/Python/3.8/lib/python/site-packages/PyQt5/Qt/lib/QtQmlModels.framework/Versions/5/QtQmlModels', 'BINARY')
----> Removed: ('QtQml', '/Users/admin/Library/Python/3.8/lib/python/site-packages/PyQt5/Qt/lib/QtQml.framework/Versions/5/QtQml', 'BINARY')
Traceback (most recent call last):
  File "/Users/admin/.pyenv/versions/3.8.9/bin/pyinstaller", line 8, in <module>
    sys.exit(run())
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/__main__.py", line 114, in run
    run_build(pyi_config, spec_file, **vars(args))
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/__main__.py", line 65, in run_build
    PyInstaller.building.build_main.main(pyi_config, spec_file, **kwargs)
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/building/build_main.py", line 725, in main
    build(specfile, kw.get('distpath'), kw.get('workpath'), kw.get('clean_build'))
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/building/build_main.py", line 672, in build
    exec(code, spec_namespace)
  File "contrib/osx/osx.spec", line 133, in <module>
    app = BUNDLE(
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/building/osx.py", line 93, in __init__
    self.__postinit__()
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/building/datastruct.py", line 160, in __postinit__
    self.assemble()
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/PyInstaller/building/osx.py", line 182, in assemble
    os.makedirs(todir)
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/os.py", line 213, in makedirs
    makedirs(head, exist_ok=exist_ok)
  File "/Users/admin/.pyenv/versions/3.8.9/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/os.py", line 223, in makedirs
    mkdir(name, mode)
NotADirectoryError: [Errno 20] Not a directory: '/private/var/folders/wh/z5_y2cv53sg24tzvtw_f_y1m0000gn/T/cirrus-ci-build/dist/ElectrumABC.app/Contents/MacOS/electrumabc/tor'
ERROR:  Could not build binary

Very frustrating

[PiRK]

Status : this needs to be rebased after #257 , or redone from scratch. The blocking item is the Mac OS build which needs to be fixed on Big Sur so I can test it and find out why electrumabc/tor is not found during this build.

[PiRK]

Done in #260