MM-18517: Plugin Marketplace (Phase 2) (#13086)

* MM-17549: use StatusNotFound when deleting plugin (#12983)

Trying to delete a plugin that does not exist should fail with a 404, not a 400.

Relates-to: https://mattermost.atlassian.net/browse/MM-17549

* MM-19630: marketplace: model ReleaseNotesURL (#13083)

Automatic Merge

* MM-20065: allow prepackaged plugin upgrade (#13076)

* MM-20065: allow prepackaged plugin upgrade

When locally installing prepackaged plugins, skip if a plugin exists with the same id and is the same or a newer version.

This is effectively a "poor man's" rework of prepackaged plugins to allow upgrade of prepackaged plugins via the marketplace. The larger plan to rework prepackaged plugins was deferred from v5.18.

Fixes: https://mattermost.atlassian.net/browse/MM-20065

* eliminate unnecessary installPlugin

* fix TestPluginSync defaults to match minio

* cleanExistingBundles

* close prepackaged filereader

* simplify

model/marketplace_plugin.go

@@ -12,10 +12,11 @@ import (
 
 // BaseMarketplacePlugin is a Mattermost plugin received from the marketplace server.
 type BaseMarketplacePlugin struct {
-	HomepageURL string    `json:"homepage_url"`
-	DownloadURL string    `json:"download_url"`
-	IconData    string    `json:"icon_data"`
-	Manifest    *Manifest `json:"manifest"`
+	HomepageURL     string    `json:"homepage_url"`
+	DownloadURL     string    `json:"download_url"`
+	ReleaseNotesURL string    `json:"release_notes_url"`
+	IconData        string    `json:"icon_data"`
+	Manifest        *Manifest `json:"manifest"`
 }
 
 // MarketplacePlugin is a state aware marketplace plugin.