test/test-env: Add setup of environment for tests

Change-Id: I9c619d9492f3109e432a9803ae0a99cb2ab45d2c

test/test-env.sh

+XDG_CONFIG_HOME="$(mktemp -t --directory jami-unittest-XXXXXX)"
+XDG_DATA_HOME="$XDG_CONFIG_HOME"
+XDG_CACHE_HOME="$XDG_CACHE_HOME"
+
+export XDG_CONFIG_HOME
+export XDG_DATA_HOME
+export XDG_CACHE_HOME
+
+SIPLOGLEVEL=5
+
+export SIPLOGLEVEL