This commit updates $license variable in all APKBUILDs to comply with
short names specified by SPDX version 3.0 [1] where possible. It was
done using find-and-replace method on substrings inside $license
variables.

Only license names were updated, not "expressions" specifying relation
between the licenses (e.g. "X and Y", "X or Y", "X and (Y or Z)") or
exceptions (e.g. "X with exceptions").

Many licenses have a version or multiple variants, e.g. MPL-2.0,
BSD-2-Clause, BSD-3-Clause. However, $license in many aports do not
contain license version or variant. Since there's no way how to infer
this information just from abuild, it were left without the variant
suffix or version, i.e. non SPDX compliant.

GNU licenses (AGPL, GFDL, GPL, LGPL) are especially complicated. They
exist in two variants: -only (formerly e.g. GPL-2.0) and -or-later
(formerly e.g. GPL-2.0+). We did not systematically noted distinguish
between these variants, so GPL-2.0, GPL2, GPLv2 etc. may mean
GPL-2.0-only or GPL-2.0-or-later. Thus GNU licenses without "+" (e.g.
GPL2+) were left without the variant suffix, i.e. non SPDX compliant.

Note: This commit just fixes format of the license names, no
verification has been done if the specified license information is
actually correct!

[1]: https://spdx.org/licenses/

* 2811e023bc75 testing/[various]: Add group and use it as primary in .pre-* scripts.
testing/buildbot-slave/buildbot-slave.pre-install
testing/buildbot/buildbot.pre-install
testing/clapf/clapf.pre-install

* c9dca511744b testing/clapf: Fix a lot of problems.
testing/clapf/APKBUILD
testing/clapf/clapf.confd
testing/clapf/clapf.initd
testing/clapf/clapf.pre-install
testing/clapf/ldflags.patch

* d36d9cd0a06e testing/buildbot: Fix some stuff.
testing/buildbot/APKBUILD
testing/buildbot/buildmaster.initd

* 15023743c545 testing/buildbot-slave: Fix some stuff.
testing/buildbot-slave/APKBUILD
testing/buildbot-slave/buildslave.initd

* APKBUILD: Leverage default_prepare and use builddir (no _).
* APKBUILD: Update url and source url.
            Original tar seems not available anymore and there are no
            tags in clapf's bitbucket repository, so use commit marked
            as release of version that was shipped before.
* APKBUILD: Introduce some constants for better DRY-ness,
            reformat package() function, create there a workdir
            (otherwise clapf won't start) and fix permissions.
* APKBUILD: make -j1 is deliberate, as it fails with more jobs,
            but I am not willing to spend any more time on this package.
* ldflags.patch: Set soname (otherwise -dev subpkg will haunt you).
* clapf.confd: Make it somewhat usable. TMPDIR seemed useless.
* clapf.initd: Rewrite using openrc-run default ssd functions.
* clapf.pre-install: Change user and group to clapf.

It has not been tested with mta, but at least it starts now if you have
virus databases present.  Run freshclam if you don't have them yet.

Fixes the problem I unintentionally brought in commit ccc056dbf9d3:
system user creation doesn't add same named group and uses nogroup as
primary group unless explicitly specified via -G.

Brings status quo regarding primary groups of users created in packages:
- testing/buildbot
- testing/buildbot-slave
- testing/clapf

It should have been part of commit a835b6916533, but was overlooked.

Now all invocations have following order of arguments (if present):

    addgroup -S -g ... GROUP
    adduser -S -u ... -D -H -h ... -s ... -G ... -g ... USER

Following rules have been applied:
- script starts with shebang !#/bin/sh followed by blank line,
- script ends with exit 0 prepended by blank line,
- only stderr of adduser, addgroup or passwd is redirected to /dev/null,
- getent passwd/group instances has been removed,
- manual checking of file and group existence has been removed,
- `|| true` instances has been removed.

Comments and line wrapping have been preserved.