cli tool - deposit end-to-end tests

[stfung77]

End to end tests for Polaris process_pending_deposits flow: Test 1: deposit_with_existing_account - creates deposit transactions (via Polaris API server) with stellar accounts that are already funded and with a trustline to the asset already added

Test2: deposit_with_account_creation - creates deposit transactions (via Polaris API server) and expects polaris to create the stellar accounts (test logic creates the asset trustline)

TODO # - implement verbose mode # - clean up structure of script