users should upgrade to syncthing by now

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/

Most of these updates is based on data from https://repology.org/,
detection based on permanent redirect from http:// to https://.

$source urls are updated when they contain $url as substring.

syncthing 0.13.10 sha512sums changed but upstream said
that no changes were made in the tarball. Maybe github
generated it again?

See: https://github.com/syncthing/syncthing/issues/4492

enabling syncthing13 package on ppc64le as go is available.
Also had to remove a tar.gz before using ln command, otherwise it
was failing the build in ppc64le.

Currently ppc64le does not have go, thus, disabling the build of
the packages that depends on golang.

This patch should be reverted once we have go enabled on ppc64le.