Add Swift package registry (#22404)

This PR adds a [Swift](https://www.swift.org/) package registry.


![grafik](https://user-images.githubusercontent.com/1666336/211842523-07521cbd-8fb6-400f-820c-ee8048b05ae8.png)

modules/setting/packages.go

@@ -39,6 +39,7 @@ var (
 		LimitSizePub         int64
 		LimitSizePyPI        int64
 		LimitSizeRubyGems    int64
+		LimitSizeSwift       int64
 		LimitSizeVagrant     int64
 	}{
 		Enabled:              true,
@@ -81,6 +82,7 @@ func loadPackagesFrom(rootCfg ConfigProvider) {
 	Packages.LimitSizePub = mustBytes(sec, "LIMIT_SIZE_PUB")
 	Packages.LimitSizePyPI = mustBytes(sec, "LIMIT_SIZE_PYPI")
 	Packages.LimitSizeRubyGems = mustBytes(sec, "LIMIT_SIZE_RUBYGEMS")
+	Packages.LimitSizeSwift = mustBytes(sec, "LIMIT_SIZE_SWIFT")
 	Packages.LimitSizeVagrant = mustBytes(sec, "LIMIT_SIZE_VAGRANT")
 }