treewide: use Software Package Data Exchange (SPDX) license identifiers

Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.

Author: syuu1228

Diff for: dist/debian/debian_files_gen.py

@@ -4,22 +4,7 @@
 # Copyright (C) 2020 ScyllaDB
 #
 
-#
-# This file is part of Scylla.
-#
-# Scylla is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Scylla is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
-#
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 import string
 import os

Diff for: install-dependencies.sh

@@ -3,22 +3,7 @@
 # Copyright (C) 2020 ScyllaDB
 #
 
-#
-# This file is part of Scylla.
-#
-# Scylla is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Scylla is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
-#
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 
 # TODO: move python dependencies from scylla main repo

Diff for: install.sh

@@ -3,22 +3,7 @@
 # Copyright (C) 2019 ScyllaDB
 #
 
-#
-# This file is part of Scylla.
-#
-# Scylla is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Scylla is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
-#
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 set -e
 

Diff for: reloc/build_reloc.sh

@@ -3,22 +3,7 @@
 # Copyright (C) 2019 ScyllaDB
 #
 
-#
-# This file is part of Scylla.
-#
-# Scylla is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Scylla is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
-#
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 print_usage() {
     echo "build_reloc.sh --dest build/scylla-python3-package.tar.gz"

Diff for: scripts/create-relocatable-package.py

@@ -4,22 +4,7 @@
 # Copyright (C) 2019 ScyllaDB
 #
 
-#
-# This file is part of Scylla.
-#
-# Scylla is free software: you can redistribute it and/or modify
-# it under the terms of the GNU Affero General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# Scylla is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
-#
+# SPDX-License-Identifier: AGPL-3.0-or-later
 
 import argparse
 import io