Disable selecting enterprise plugins with no license (#28758) (#28859)

* Add unlicensed property to plugins

* Disable selecting unlicensed plugin

* Add customizable plugin market place url

* License: workaround enabled only in enterprise

* linter

* Move licensing info to front end

* Update pkg/services/licensing/oss.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/services/licensing/oss.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/setting/setting.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/setting/setting.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/api/frontendsettings.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update sample.ini

* Update docs

* Update packages/grafana-runtime/src/config.ts

Co-authored-by: Torkel Ödegaard <torkel@grafana.org>

* Update public/app/features/datasources/state/buildCategories.ts

Co-authored-by: Torkel Ödegaard <torkel@grafana.org>

* Update pkg/api/frontendsettings.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Update pkg/setting/setting.go

Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

* Fix spelling

Co-authored-by: Leonard Gram <leo@xlson.com>
Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>
Co-authored-by: Torkel Ödegaard <torkel@grafana.org>
(cherry picked from commit 9b90ff2961)

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>

pkg/setting/setting.go

@@ -273,6 +273,7 @@ type Cfg struct {
 	PluginsAppsSkipVerifyTLS bool
 	PluginSettings           PluginSettings
 	PluginsAllowUnsigned     []string
+	MarketplaceURL           string
 	DisableSanitizeHtml      bool
 	EnterpriseLicensePath    string
 
@@ -796,6 +797,7 @@ func (cfg *Cfg) Load(args *CommandLineArgs) error {
 		plug = strings.TrimSpace(plug)
 		cfg.PluginsAllowUnsigned = append(cfg.PluginsAllowUnsigned, plug)
 	}
+	cfg.MarketplaceURL = pluginsSection.Key("marketplace_url").MustString("https://grafana.com/grafana/plugins/")
 	cfg.Protocol = Protocol
 
 	// Read and populate feature toggles list