Revert "qof_book_get_qof_instance for Company info"

This reverts commit c8de5e6136f553490823688afec2795f9263d798.
Revert "Some doc about KVP usage"

This reverts commit 1eb6e8c7f74dd5a9ce499fffc5c9d933cd31a303.
Revert "Python bindings KVP support"

This reverts commit 36627c352b51d7edabec8ed0e7095bedd046fdc0.
Revert "Extending the invoice by adding Company info"

This reverts commit aef425b67fe9da65638ab8856e92e57e2931a6d9.