The CMakeLists.txt now (almost) supports both qt5 and qt6 (for qt6, qt5_add_translation must be replaced by the proper one). The compilation instructions were not up to date, they have been updated.

(so those who want to skip installing qt5-tools can compile without!)

I did not manage to have Inishell opening up in German, but at least the translation files can be generated and don't stop the compilation

Also the first effort to address issue 884

Don't expect it to work yet!

(otherwise a double click on inishell starts a console that launches inishell)

And moved the binary inishell into a "bin" directory

This is issue 869 and is required for several reasons: 1) to make Inishell more
similar to MeteoIO, Snowpack, etc 2) because Qt6 is moving to CMake in
replacement of qmake 3) because it will "easily" allow creating native packages
for several platforms.