ci: add job performing static analysis on GitLab CI

Our GitHub Workflows definitions have a static analysis job that
runs the following tasks:

  - Coccinelle to check for suggested refactorings.

  - `make hdr-check` to check for missing includes or forward
    declarations in our header files.

  - `make check-pot` to check our translations for issues.

  - `./ci/check-directional-formatting.bash` to check whether our
    sources contain any Unicode directional formatting code points.

Add an equivalent job to our GitLab CI definitions.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

ci/install-docker-dependencies.sh

@@ -21,7 +21,7 @@ linux-musl)
 		apache2 apache2-http2 apache2-proxy apache2-ssl apache2-webdav apr-util-dbd_sqlite3 \
 		bash cvs gnupg perl-cgi perl-dbd-sqlite >/dev/null
 	;;
-linux-*)
+linux-*|StaticAnalysis)
 	# Required so that apt doesn't wait for user input on certain packages.
 	export DEBIAN_FRONTEND=noninteractive
 
@@ -31,6 +31,11 @@ linux-*)
 		perl-modules liberror-perl libauthen-sasl-perl libemail-valid-perl \
 		libdbd-sqlite3-perl libio-socket-ssl-perl libnet-smtp-ssl-perl ${CC_PACKAGE:-${CC:-gcc}} \
 		apache2 cvs cvsps gnupg libcgi-pm-perl subversion
+
+	if test "$jobname" = StaticAnalysis
+	then
+		apt install -q -y coccinelle
+	fi
 	;;
 pedantic)
 	dnf -yq update >/dev/null &&