gnucash maint: Multiple changes pushed

[Geert Janssens]

Updated	 via  https://github.com/Gnucash/gnucash/commit/09b3ce23 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/806d0b31 (commit)
	 via  https://github.com/Gnucash/gnucash/commit/1d4673ed (commit)
	from  https://github.com/Gnucash/gnucash/commit/c07164f4 (commit)



commit 09b3ce2382cd64efe5a6bf75eb33ad1935acfb96
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Sat Oct 16 19:02:17 2021 +0200

    Revert "Add structure to map migrated preferences to old ones"
    
    This reverts commit c6103a5c171f459b6ca070c61bcde939885ae613.

commit 806d0b31576a1ba196907b8fa41c93a7f1c77295
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Sat Oct 16 19:02:10 2021 +0200

    Revert "GSettings - make most of the api private"
    
    This reverts commit 26b2d7ca7878776a7c6777cd30e1b19185b72983.

commit 1d4673ed2a920c2f902ec6eecd8b18e481deeda2
Author: Geert Janssens <geert at kobaltwit.be>
Date:   Sat Oct 16 19:02:04 2021 +0200

    Revert "GSettings - rework internal helper functions to use more C++"
    
    This reverts commit 24fa289952257cb8a2f2b9d59024be59d05888e3.



Summary of changes:
 libgnucash/app-utils/gnc-gsettings.cpp | 277 ++++++-----------
 libgnucash/app-utils/gnc-gsettings.h   | 550 +++++++++++++++++++++++++++++++++
 libgnucash/app-utils/gnc-prefs-utils.c |   1 -
 3 files changed, 639 insertions(+), 189 deletions(-)