Setup and migration UI refactor (#1190)

* Make config instance-based
* Remove config dependency in paths
* Refactor config init
* Allow startup without database
* Get system status at UI initialise
* Add setup wizard
* Cache and Metadata optional. Database mandatory
* Handle metadata not set during full import/export
* Add links
* Remove config check middleware
* Stash not mandatory
* Panic on missing mandatory config fields
* Redirect setup to main page if setup not required
* Add migration UI
* Remove unused stuff
* Move UI initialisation into App
* Don't create metadata paths on RefreshConfig
* Add folder selector for generated in setup
* Env variable to set and create config file.
Make docker images use a fixed config file.
* Set config file during setup

pkg/api/resolver_query_configuration.go

@@ -34,6 +34,7 @@ func makeConfigResult() *models.ConfigResult {
 }
 
 func makeConfigGeneralResult() *models.ConfigGeneralResult {
+	config := config.GetInstance()
 	logFile := config.GetLogFile()
 
 	maxTranscodeSize := config.GetMaxTranscodeSize()
@@ -81,6 +82,7 @@ func makeConfigGeneralResult() *models.ConfigGeneralResult {
 }
 
 func makeConfigInterfaceResult() *models.ConfigInterfaceResult {
+	config := config.GetInstance()
 	menuItems := config.GetMenuItems()
 	soundOnPreview := config.GetSoundOnPreview()
 	wallShowTitle := config.GetWallShowTitle()