[BRANDING] add X-Forgejo-* headers

(cherry picked from commit 0a3388f93f)
(cherry picked from commit 7eba0a440a)
(cherry picked from commit eb9646c7ef)
(cherry picked from commit f1972578f5)

Conflicts:
(cherry picked from commit 7f96222fb4)
(cherry picked from commit e3c7c9fe7b)
(cherry picked from commit 84fdead902)
(cherry picked from commit 85148e1196)
(cherry picked from commit c0086bd70d)
(cherry picked from commit d1e31ef318)
(cherry picked from commit 681d3ed5c4)
(cherry picked from commit 76a3001f5b)
(cherry picked from commit a55a9567d3)
(cherry picked from commit aa7adc167d)
(cherry picked from commit d5354cb52c)
(cherry picked from commit 472c489996)
(cherry picked from commit dc816d065b)
(cherry picked from commit 4795f9ea85)
(cherry picked from commit ddd4ae5343)
(cherry picked from commit 0e95f2a36b)
(cherry picked from commit 47a41a4e7b)
(cherry picked from commit d4416fcd3e)
(cherry picked from commit f279d153b6)
(cherry picked from commit 959f908ffd)
(cherry picked from commit 82df953101)
(cherry picked from commit 8f8c9fd9e3)
(cherry picked from commit d4a0db7706)
(cherry picked from commit 44594d6239)
(cherry picked from commit 62b1de579e)
(cherry picked from commit 507abee353)
(cherry picked from commit 8c36ac42c7)
(cherry picked from commit 72f74067f4)
(cherry picked from commit 8e5a9e187b)
(cherry picked from commit cff8f43c7e)
(cherry picked from commit 13544bbde8)
(cherry picked from commit 5b7a117347)
(cherry picked from commit ab61310f10)
(cherry picked from commit 537c214c28)
(cherry picked from commit 91a6c59c9d)

modules/httpcache/httpcache_test.go

@@ -18,6 +18,9 @@ func countFormalHeaders(h http.Header) (c int) {
 		if strings.HasPrefix(k, "X-Gitea-") {
 			continue
 		}
+		if strings.HasPrefix(k, "X-Forgejo-") {
+			continue
+		}
 		c++
 	}
 	return c