Added set up path for tarantool datadir

extra/dist/CMakeLists.txt

 # Scripts for a tarantoolctl packaging
 set(SYSV_INITD_PATH ${CMAKE_INSTALL_LIBDIR}/tarantool/tarantool.init)
+# Default path to data in default/tarantool
+if (NOT TARANTOOL_DATADIR)
+    set(TARANTOOL_DATADIR "/var/lib/tarantool")
+endif()
+message (STATUS "TARANTOOL_DATADIR: ${TARANTOOL_DATADIR}")
+
 configure_file("tarantool.service.in" "tarantool.service")
 configure_file(default/tarantool.in default/tarantool)
 

extra/dist/default/tarantool.in

 -- Options for Tarantool
 default_cfg = {
     pid_file   = "/var/run/tarantool", -- will become pid_file .. instance .. '.pid'
-    wal_dir    = "/var/lib/tarantool", -- will become wal_dir/instance/
-    snap_dir   = "/var/lib/tarantool", -- snap_dir/instance/
-    sophia_dir = "/var/lib/tarantool", -- will become sophia_dir/sophia/instance/
+    wal_dir    = "@TARANTOOL_DATADIR@", -- will become wal_dir/instance/
+    snap_dir   = "@TARANTOOL_DATADIR@", -- snap_dir/instance/
+    sophia_dir = "@TARANTOOL_DATADIR@", -- will become sophia_dir/sophia/instance/
     logger     = "/var/log/tarantool", -- logger/instance .. '.log'
     username   = "tarantool",
 }