chore: return vector of SequencerNodeConfig in create config function

[nadin-Starkware]

Stack:

• feat: add test case for remote connection flow #2647
• chore: add mock_system_mode to create config function #2646
• chore: return vector of SequencerNodeConfig in create config function #2638 ⬅
• chore: add get_http_server_config function #2637
• chore: change sequencer_node_handle type #2636
• chore: add serial_test crate #2635
• chore: add mock system mode enum #2632

⚠️ Part of a stack created by spr. Do not merge manually using the UI - doing so may have unexpected results.

[reviewable-StarkWare]

This change is 

[Itay-Tsabary-Starkware]

Reviewable status: 0 of 3 files reviewed, 2 unresolved discussions (waiting on @nadin-Starkware)

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crates/starknet_integration_tests/src/flow_test_setup.rs line 38 at r1 (raw file):

    pub task_executor: TokioExecutor,
    pub sequencer_0: SequencerSetup,
    pub sequencer_1: SequencerSetup,

These vars represent the dpeloyed nodes.
Each should have its own config, handle, storage, etc., all detailed within the SequencerSetup.

I would have expected this pr to add a function similar to new_from_tx_generator(tx_generator: &MultiAccountTransactionGenerator), e.g., new_from_tx_generator_remote_setup(tx_generator: &MultiAccountTransactionGenerator) (just a temp name), that will init FlowTestSetup in the expected manner.

Code quote:

    pub sequencer_0: SequencerSetup,
    pub sequencer_1: SequencerSetup,

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crates/starknet_integration_tests/src/flow_test_setup.rs line 99 at r1 (raw file):

    pub sequencer_node_handles: Vec<JoinHandle<Result<(), anyhow::Error>>>,

    pub configs: Vec<SequencerNodeConfig>,

I'm confused, I thought there each SequencerSetup is exactly a single deployment. If so, then it should hold exactly one handle and exactly one config.

Code quote:

    pub sequencer_node_handles: Vec<JoinHandle<Result<(), anyhow::Error>>>,

    pub configs: Vec<SequencerNodeConfig>,