fixup! client: move sources into separate directory

Previous cleanup attempt broke installation on systems without libedit.
client-install has to be defined at least as .PHONY target.
(I want to avoid if spagethi outside of client.mk.)
9 jobs for <span class="ref-name">cleanup-fixup</span> in 2 minutes and 27 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  Build
passed #81296
docker linux amd64
build:linux:amd64

00:00:30

 
  Test
passed #81300
docker linux amd64
deckard:linux:amd64

00:00:34

passed #81299
docker linux amd64
installcheck:linux:amd64

00:00:23

passed #81301
docker linux amd64
installcheck:valgrind:linux:amd64

00:00:30

passed #81297
docker
lint:lua

00:00:19

passed #81303
docker linux amd64
respdiff:linux:amd64

00:01:40

passed #81298
docker linux amd64
test:linux:amd64

00:00:23

passed #81302
docker linux amd64
test:linux:amd64:valgrind

00:00:30

 
  Deploy
passed #81304
docker linux amd64
coverage:linux:amd64

00:00:15

65.6%