[GITEA] Add password length check on install page

- Resolves #271
- Ensure that the adminstrator password is at least `MIN_PASSWORD_LENGTH`.

(cherry picked from commit 28cb04c3f5)
(cherry picked from commit 95371ebd92)
(cherry picked from commit a134288ab6)
(cherry picked from commit 4202f052cb)
(cherry picked from commit 510b7467d3)
(cherry picked from commit f3a6e1f121)
(cherry picked from commit f340508819)
(cherry picked from commit b891bb176d)
(cherry picked from commit 1a1bfc38cc)
(cherry picked from commit 083d5aefed)
(cherry picked from commit 4586096be9)
(cherry picked from commit 039fa20cc8)
(cherry picked from commit 3ec9cb5f59)
(cherry picked from commit 00be0eee37)
(cherry picked from commit a156603002)
(cherry picked from commit 4d305e7774)
(cherry picked from commit 51e8f21202)

routers/install/install.go

@@ -358,6 +358,12 @@ func SubmitInstall(ctx *context.Context) {
 			ctx.RenderWithErr(ctx.Tr("form.password_not_match"), tplInstall, form)
 			return
 		}
+		if len(form.AdminPasswd) < setting.MinPasswordLength {
+			ctx.Data["Err_Admin"] = true
+			ctx.Data["Err_AdminPasswd"] = true
+			ctx.RenderWithErr(ctx.Tr("auth.password_too_short", setting.MinPasswordLength), tplInstall, form)
+			return
+		}
 	}
 
 	// Init the engine with migration