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
Eliminate not used includes and replace some more includes
with forward declarations where appropriate.
Signed-off-by: Pavel Solodovnikov <pa.solodovnikov@scylladb.com>
This adds a requires_thread predicate to functions and propagates that
up until we get to code that already returns futures.
We can then use the predicate to decide if we need to use
seastar::async.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
