test(e2e): end to end testing infrastructure for VAAS

[giuliostramondo]

The e2e tests can be run with make test-e2e:

• Setup docker container for provider, consumer and relayer
• Creates IBC connection and channel
• Performs basic sanity tests on VAAS (defined in e2e_vaas_test.go):

1. producer and consumer produce blocks
2. consumer is registered on producer
3. validator set updates are synced from producer to consumer.

Closes #4