Return to previous state of vector joins if the vector props dialog was cancelled
Followup #10912 - detect cycles in joins and reject joins that would create cycle

Cycle would otherwise cause infinite loop when updating fields and it does not make sense
followup ui rename (followup 13eb726d)
[QgsMapToolIdentifyFeature] allow initializing without any layer
[QgsRelationReferenceWidget] make error label multiline
Add options for color buttons, allowing them to be used in a swatch
type mode.
Allow setting color button to invalid color resulting in a blank
button. Default to invalid color for new buttons.
Fix loss of hue information with slider widgets
Add action menu to attribute dialog
Add icon support to actions
Add user data to identify actions to actionmenu
[QgsActionMenu] use correct level of actions
[QgsActionMenu] use ActionData to trigger actions
[QgsActionMenu] fix return feature
improved identify menu with a dedicated class
[SIP] add missing argument in QgsEditorWidgetRegistry::QgsEditorWidgetWrapper
[FEATURE] New custom QGIS color picker dialog. Basically
it's a Frankenstein's monster of the best bits of lots of other color
picker implementations. Features include:
- Sliders for hue, saturation, value, red, green, blue color components
- Alpha slider
- Option to copy/paste html color codes (in a variety of formats)
- Before/after color preview, with alpha preview
- Interactive 2D color ramp widget
- Hue wheel/triangle widget
- Editable color swatch lists
- Live color sampler with option to sample over a set radius
- Supports interaction with other apps via drag and drop of colors (OS support
dependant)
- Option to disable the dialog and use the native picker dialog instead (TODO:
make the dialog so awesome that even @dakcarto switches across...)

Credit for icons goes to 3nids!
Fix widget registry (SIP), few fixes for relation reference widget
Pass attribute editor context for widgets on the attribute table

Fixes relation reference widget in attribute table
Fix sip for QgsMapLayerActionRegistry