Keeping a pointer to the actual file history inside a special
file history menu led to many cases of use after free crashes,
so instead rework the actual file history to add the menu
items.
Fixes https://gitlab.com/kicad/code/kicad/issues/3741
CHANGED: Settings are now stored in versioned sub-directories
ADDED: First-run dialog for migrating settings from a previous version
CHANGED: Settings are now stored as JSON files instead of wxConfig-style INI files
CHANGED: Color settings are now all stored in a separate settings file
CHANGED: The symbol editor and footprint editor now have their own settings files
CHANGED: Color settings are no longer exposed through BOARD object
CHANGED: Page layout editor now uses Eeschema's color scheme
Settings are now managed through a central SETTINGS_MANAGER held by PGM_BASE.
Existing settings will be migrated from the wxConfig format on first run of each application.
Per-application settings are now stored in one class for each application.
Delete the copy ctor and assignment operator to start with, but
even then the separate apps each have their own statically allocated
copy of the common actions. So we need to update all of them, which
also means having the kicad manager frame's set of actions on hand).
This changelist also adds a Clear Hotkey Assignment function since
the hotkeys set is now likely to be sparse with respect to the
actions.
