CI: tidy up scripts

- Add SPDX headers
 - Indent consistently (tabs, not a mix of 2-space, 4-space, and tabs)

The scripts were originally added without a license header.
Since they are simple, and re-usable, and not particularly
interesting, I've made the license explicitly 2-clause BSD.
This is unlike the rest of Calamares, which is GPLv3+; the
build system and support scripts are not the software itself.

ci/txpull.sh

@@ -1,4 +1,18 @@
 #!/bin/sh
+
+### LICENSE
+# === This file is part of Calamares - <https://github.com/calamares> ===
+#
+#   SPDX-License-Identifier: BSD-2-Clause
+#   SPDX-FileCopyrightText: 2017-2020 Adriaan de Groot <groot@kde.org>
+#   SPDX-FileCopyrightText: 2015-2016 Teo Mrnjavac <teo@kde.org>
+#
+#   This file is Free Software: you can redistribute it and/or modify
+#   it under the terms of the 2-clause BSD License.
+#
+### END LICENSE
+
+### USAGE
 #
 # Fetch the Transifex translations for Calamares and incorporate them
 # into the source tree, adding commits of the different files.
@@ -6,6 +20,8 @@
 # Run this (occasionally) at the top-level directory to get
 # new translations. See also CMakeLists.txt and ci/txstats.py
 # for update instructions.
+#
+### END USAGE
 
 ### INITIAL SETUP
 #

ci/txpush.sh

@@ -1,13 +1,33 @@
 #!/bin/sh
+
+### LICENSE
+# === This file is part of Calamares - <https://github.com/calamares> ===
+#
+#   SPDX-License-Identifier: BSD-2-Clause
+#   SPDX-FileCopyrightText: 2017-2020 Adriaan de Groot <groot@kde.org>
+#   SPDX-FileCopyrightText: 2015-2016 Teo Mrnjavac <teo@kde.org>
+#
+#   This file is Free Software: you can redistribute it and/or modify
+#   it under the terms of the 2-clause BSD License.
+#
+### END LICENSE
+
+### USAGE
 #
 # Extract translations from Calamares source and send them
-# to Transifex.
+# to Transifex. Also (forcibly) updates the git "translation"
+# tag to document that source texts were updated and sent;
+# this is used by txcheck.sh to ensure that there's enough
+# time between updates and releases, and that strings don't
+# change between updates and releases.
 #
 # Run this at the top-level.
 #
 # Use the --no-tx option to do the extraction, but not the
 # pushing-to-Transifex part. This can be useful to check for
 # new strings or when testing the tools themselves.
+#
+### END USAGE
 
 ### INITIAL SETUP
 #