Config overlays

Update check overlay

Starting with version 1.5.0 OctoPrint now supports the use of a centralized update check overlay, to allow for setting new software update configs for plugins that e.g. were abandoned by their original maintainer and have been adopted by a new one at a new repository location, or plugins that shipped with a broken default update config.

The overlay is hosted here on plugins.octoprint.org as a JSON file and currently contains the following entries:

Plugin	Overlay
`octoprint`	{"user":"OctoPrint"}
Detailed Progress	{"user":"tpmullan"}
FilamentManager	{"user":"OllisGit"}
OctoKlipper	{"user":"AliceGrey"}
CostEstimation	{"user":"Hillshum","pip":"https://github.com/Hillshum/OctoPrint-CostEstimation/releases/download/{target_version}/master.zip"}
Filament Sensor Reloaded	{"user":"nickmitchko"}
Marlin EEPROM Editor	{"user":"cp2004"}
Printer Statistics	{"user":"AlexVerrico","repo":"octoprint-stats"}
Continuous Print	{"user":"smartin015"}
M73 ETA Override	{"user":"gdombiak"}
WebcamTab	{"user":"gruvin"}
OctoPrint-Mmu2filamentselect	{"user":"tkoecker"}
Slack	{"user":"mkevenaar"}
MetadataPreprocessor	{"user":"awenelo"}
HeaterTimeout	{"user":"Andy-ch"}
Octoprint-Smart-Filament-Sensor	{"user":"Royrdan","pip":"https://github.com/Royrdan/Octoprint-Smart-Filament-Sensor/archive/{target_version}.zip"}
`ledstripcontrol`	{"user":"gbonesso","pip":"https://github.com/gbonesso/OctoPrint-LEDStripControl/archive/{target_version}.zip"}
Exclude Region	{"user":"bradcfisher"}
SlicerSettingsParser	{"user":"larsjuhw"}
OctoPrint-Webhooks	{"user":"derekantrican","pip":"https://github.com/derekantrican/OctoPrint-Webhooks/archive/{target_version}.zip"}
OctoLight	{"user":"thomst08"}
PrintJobHistory	{"user":"vojtakaniok","pip":"https://github.com/vojtakaniok/OctoPrint-PrintJobHistory/releases/download/{target_version}/main.zip"}
SpoolManager	{"user":"WildRikku","pip":"https://github.com/WildRikku/OctoPrint-SpoolManager/releases/download/{target_version}/main.zip"}