Standardize po headers

Signed-off-by: Guido Günther <guido.gunther@puri.sm>

Closes: #39

po/de.po

-# German translations for phosh package.
+# German translations for phosh
 # Copyright (C) 2018 THE phosh'S COPYRIGHT HOLDER
 # This file is distributed under the same license as the phosh package.
-# Automatically generated, 2018.
+# Guido Günther <agx@sigxcpu.org>, 2018
 #
 msgid ""
 msgstr ""

po/es.po

-# Spanish translation for phosh package.
+# Spanish translation for phosh
 # Copyright (C) 2018 THE phosh'S COPYRIGHT HOLDER
 # This file is distributed under the same license as the phosh package.
 # Alberto Fanjul <albfan@gnome.org>, 2018.

po/it.po

+# Italian translation for phosh
 # Copyright (C) YEAR THE PACKAGE'S COPYRIGHT HOLDER
 # This file is distributed under the same license as the phosh package.
-# FIRST AUTHOR <ant.pandolfo@gmail.com>, 2018.
+# Ant Pandolfo <ant.pandolfo@gmail.com>, 2018.
 #
 msgid ""
 msgstr ""