Added script for generating celestia.pot template

Update celestia.pot (generated by script)

Co-Authored-By: Ignacio Losiggio <iglosiggio@gmail.com>

update_pot.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+extractrc $(find -name \*.ui -o -name \*.rc -o -name \*.kcfg) > testrc.cpp
+xgettext -ki18n -k_ -F -j \
+         -d celestia --package-name=celestia --package-version=1.7.0 --msgid-bugs-address=chris@teyssier.org --copyright-holder="Chris Laurel" \
+         $(find . -name \*.c -o -name \*.cpp -o -name \*.cc -o -name \*.h -o -name \*.hpp -o -name \*.qml) -o po/celestia.pot
+rm testrc.cpp