bash error handling and reporting is atrocious. Without -e it will
just ignore errors. With -e it will stop on errors, but not report
where the error happened (apart from exiting itself with an error code).
Improve that with the `trap ERR` command. Note that this won't be invoked
on intentional error exit with `exit 1`.
We apply this on every bash script that contains -e or that it appears
trivial to set it in. Non-trivial scripts without -e are left unmodified,
since they might intentionally invoke failing scripts.
Closesscylladb/scylladb#22747
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.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
Supported cross build by running CentOS7 on docker, now it's able to build
on Fedora.
It also supported switch container image, tested on Oracle Linux 7 and
CentOS 7/8.
