- drop explicit package requirements
- split binary package and documentation from dynamic library package
- merge back Botan2 package to Botan with changelog history
- drop Botan patches
aarch64-support.patch - doesn't seem to be required anymore
Botan-fix_install_paths.patch - doesn't seem to be required
no-cpuid-header.patch - SLE11 not target anymore
Botan-fix_pkgconfig.patch - this seem to be wrong
Botan-no-buildtime.patch - not needed anymore
dont-set-mach-value.diff - doesn't apply, unclear and undocumented why it is there
Botan-inttypes.patch - not required
Botan-ull_constants.patch.bz2 - no reason anymore

- change group of libbotan-%{version_suffix} to 'System/Libraries' as
requested on review

- Don't drop -fstack-clash-protection for openSUSE 42.3 - we just
need the Update repository present.

- Rename libbotan-devel to libbotan2-devel. We can't have clashing
packages in the archive because Botan1 and Botan2 provide the
same -devel binary. Botan2 is also no API compatible with Botan.

- fix expected version after bump in baselibs.conf too

- fix unknown flag -fstack-clash-protection for openSUSE 42.3
- rename to Botan2
- drop Botan2-INT_MAX.patch as not needed anymore
- Bump to libbotan 2.4
Changes and new features: (forwarded request 578006 from sleep_walker)