container: move out of toplevel

This allows slightly easier use of the vanity url. This also provides some disambiguation between low level containers and hakurei app containers.

Signed-off-by: Ophestra <cat@gensokyo.uk>

container/executable.go

@@ -0,0 +1,26 @@
+package container
+
+import (
+	"log"
+	"os"
+	"sync"
+)
+
+var (
+	executable     string
+	executableOnce sync.Once
+)
+
+func copyExecutable() {
+	if name, err := os.Executable(); err != nil {
+		msg.BeforeExit()
+		log.Fatalf("cannot read executable path: %v", err)
+	} else {
+		executable = name
+	}
+}
+
+func MustExecutable() string {
+	executableOnce.Do(copyExecutable)
+	return executable
+}