.gitignore: Rename the ring pattern to jami.

Also add packages to .dockerignore, as this output directory can grow
to multiple GiBs.

Change-Id: I17b8b0a6d7be535d888232952c346b45c3224eb1

.dockerignore

@@ -6,7 +6,8 @@ client-qt
 client-uwp
 daemon
 lrc
-ring_*
+jami_*
+packages
 plugins
 .git
 */.git

.gitignore

@@ -5,7 +5,7 @@
 env
 docs/build
 packages
-ring_*.tar.gz
+jami_*.tar.gz
 Makefile.packaging.distro_targets
 repositories
 manual-download