Move to yaml-based configuration

This commit updates the configuration to be yaml-based and updates the
configuration to read in a yaml file.

internal/config/validators/collection.go

@@ -0,0 +1,32 @@
+package validators
+
+import (
+	"github.com/FAU-CDI/wisski-distillery/pkg/environment"
+	"github.com/FAU-CDI/wisski-distillery/pkg/validator"
+)
+
+// New creates a new set of standard validators for the configuration
+func New(env environment.Environment) validator.Collection {
+	coll := make(validator.Collection)
+
+	validator.Add(coll, "nonempty", ValidateNonempty)
+
+	validator.Add(coll, "directory", func(value *string, dflt string) error {
+		return ValidateDirectory(env, value, dflt)
+	})
+	validator.Add(coll, "file", func(value *string, dflt string) error {
+		return ValidateFile(env, value, dflt)
+	})
+
+	validator.Add(coll, "domain", ValidateDomain)
+	validator.AddSlice(coll, "domains", ",", ValidateDomain)
+	validator.Add(coll, "https", ValidateHTTPSURL)
+	validator.Add(coll, "slug", ValidateSlug)
+	validator.Add(coll, "email", ValidateEmail)
+
+	validator.Add(coll, "positive", ValidatePositive)
+	validator.Add(coll, "port", ValidatePort)
+
+	validator.Add(coll, "duration", ValidateDuration)
+	return coll
+}