Create pages from _content.gotmpl

Closes #12427
Closes #12485
Closes #6310
Closes #5074

config/configProvider.go

@@ -41,6 +41,7 @@ type AllProvider interface {
 	Dirs() CommonDirs
 	Quiet() bool
 	DirsBase() CommonDirs
+	ContentTypes() ContentTypesProvider
 	GetConfigSection(string) any
 	GetConfig() any
 	CanonifyURLs() bool
@@ -75,6 +76,15 @@ type AllProvider interface {
 	EnableEmoji() bool
 }
 
+// We cannot import the media package as that would create a circular dependency.
+// This interface defineds a sub set of what media.ContentTypes provides.
+type ContentTypesProvider interface {
+	IsContentSuffix(suffix string) bool
+	IsContentFile(filename string) bool
+	IsIndexContentFile(filename string) bool
+	IsHTMLSuffix(suffix string) bool
+}
+
 // Provider provides the configuration settings for Hugo.
 type Provider interface {
 	GetString(key string) string