Add rakudo.eclass and dev-raku/*

rakudo.eclass requires install-dist.raku installed by a modified version
of dev-lang/rakudo. Gentoo overlay's dev-lang/rakudo doesn't install
install-dist.raku.

rakudo.eclass is minimal and elegant. dev-raku/* packages depend on
rakudo.eclass.

Signed-off-by: amano.kenji <amano.kenji@proton.me>

dev-raku/JSON-Fast/JSON-Fast-0.17-r1.ebuild

@@ -0,0 +1,15 @@
+# Copyright 2020-2022 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI="8"
+
+inherit rakudo
+
+DESCRIPTION="A naive imperative JSON parser in pure Raku"
+HOMEPAGE="https://raku.land/cpan:TIMOTIMO/JSON::Fast"
+SRC_URI="mirror://cpan/authors/id//T/TI/TIMOTIMO/Perl6/${P}.tar.gz"
+LICENSE="Artistic-2"
+SLOT="0"
+KEYWORDS="~amd64"
+RESTRICT="primaryuri"
+DOCS="README.md Changes"