[FEATURE] Port editor widgets to new API

Create a new widget for for attribute form

fix #10281
fix #7319
fix #7013
fix #9335
fix #4417
[FEATURE] new edit type: date/time edit
Add GUI_EXPORT and warning fix
[FEATURE] Quick field field calc bar (like Excel) in attribute table
fix windows build
Fix combo name in fielc calc bar
german translation update and a translation string fix
[FEATURE][composer] Add a 'predefined scales' mode to atlas maps, which sets an atlas maps' extent to the largest predefined scale which fits the atlas feature. Scales are taken from the project's predefined scales, or the global predefined scales.
[composer] Small improvements to API docs
Mask renderer: fix clone()
Atlas predefined scales: reload project scales before each preview action
Mask renderer: do not store temporary features anymore
Updated IT GUI translation
restore addLegendLayerAction and related functions after legend redesign
[layertree] move implementation of legend actions to QgsAppLayerTreeViewMenuProvider
Updated indentation
Merge pull request #1382 from Oslandia/atlas_predefined_patch

Atlas predefined scales: reload project scales before each preview action
Merge pull request #1338 from manisandro/line_multi_labeling

Line multi labeling
[TRANSUP] nb by James

Signed-off-by: Werner Macho <werner.macho@gmail.com>
[layertree] Use group icon like the one from old legend