Revert "Say that a deploy keeps only an app's volumes when the app has none"

The owner asked for this commit to be reverted in full
(#254 (comment)). It
removes the no-volume-mounts sentence from the app page and the deploy
log, the constant and tests behind it, the README sentence, and its
TODO.md entry. Later TODO.md entries stay. #248
stays closed as rejected.

Model: opus-5-5

internal/handlers/app.go

@@ -21,7 +21,6 @@ import (
 	"sneak.berlin/go/upaas/internal/database"
 	"sneak.berlin/go/upaas/internal/models"
 	"sneak.berlin/go/upaas/internal/service/app"
-	"sneak.berlin/go/upaas/internal/service/deploy"
 	"sneak.berlin/go/upaas/templates"
 )
 
@@ -195,7 +194,6 @@ func (h *Handlers) HandleAppDetail() http.HandlerFunc {
 			"EnvVars":          envVars,
 			"Labels":           labels,
 			"Volumes":          volumes,
-			"NoVolumesWarning": deploy.NoVolumesWarning,
 			"Ports":            ports,
 			"Deployments":      deployments,
 			"LatestDeployment": latestDeployment,