* main/canary_events: assign low resources to the canary events skein tasks

Signed-off-by: Balthazar Rouberol <brouberol@wikimedia.org>

* common: Define a helper allowing to override kubernetes executor pod resources

Signed-off-by: Balthazar Rouberol <brouberol@wikimedia.org>

* Move kubernetes-related utils to a dedicated common module

Signed-off-by: Balthazar Rouberol <brouberol@wikimedia.org>