Add RPM spec

[kapsh]

No description provided.

[kapsh]

Builds, installs and works on Fedora 40. Can be tested using commands

cd dist
spectool -g *.spec
fedpkg mockbuild

or maybe older reliable

dnf builddep *.spec
rpmbuild -bb *.spec

(without extra steps to configure buildroot).

Won't build on Oracle Linux 9 or RHEL 9 (but only because of fancy shell completion locations macros added in 2022 which is too new for the enterprise).

[kapsh]

Updated for version 0.7.

I noticed that shell completions are missing from installed files after switching build system. If that was a mistake I have meson snippet to install them ready (though this will require another PR merged in point release or spec would become ugly).