Various plugin fixes (#5577)

* Fix: Plugin updates do not work

* Offer install on disabled plugins when different version

This will:
* Clear any previous pending actions of a plugin if you click uninstall
* Show the plugin version that was disabled
* Show an update button on disabled plugins instead of install
* if a plugin is scheduled to be installed/updated, it will show which version was scheduled to be updated. If a newer version if available than the scheduled one, it will show an option to switch to that

* Ensure disabled plugins don't get loaded

* View fixes

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Co-authored-by: d11n <mail@dennisreimann.de>

BTCPayServer/Controllers/UIServerController.Plugins.cs

@@ -55,7 +55,7 @@ namespace BTCPayServer.Controllers
             public IEnumerable<PluginService.AvailablePlugin> Available { get; set; }
             public (string command, string plugin)[] Commands { get; set; }
             public bool CanShowRestart { get; set; }
-            public string[] Disabled { get; set; }
+            public Dictionary<string, Version> Disabled { get; set; }
             public Dictionary<string, AvailablePlugin> DownloadedPluginsByIdentifier { get; set; } = new Dictionary<string, AvailablePlugin>();
         }