utils/utf8.c: move includes outside of namespaces
utils/utf8.c: move includes outside of namespaces

Including in the middle of a namespace is not a good practice.

Signed-off-by: Botond Dénes <a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>
Message-Id: <20210528142502.962947-1-a584fa4d75a0a85d721f44fb6e06315a2853b0b6@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla