What ❔

• ⚠️ Docs are missing or outdated in many places -- I found myself spending too much time keeping them up to date while the framework in active development, so I gave up. Will update all the docs at once when the framework is more or less finalized.
• ❗ Removes the ResourceProvider abstraction. State keeper task finally showed that it brings more problems than solutions. Main implication: now ordering of layers matters ("base" layers should go first), but hopefully it shouldn't cause too much problems.
• Makes it possible to add resources to the context without
• Creates PoolsLayer that was previously handled by ResourceProvider.
• Creates SequencerFeeInputLayer and ObjectStoreLayer.
• Adds notion of unique resource (to have Box<smth> as a non-shareable resource, like IO).
• Adds support for state keeper (in form of StateKeeperLayer, MempoolIOLayer, and MainNodeBatchExecutorBuilderLayer).
• Rewamps the main node example to look better.

Current "external" point of view for the framework:

fn main() -> anyhow::Result<()> {
    #[allow(deprecated)] // TODO (QIT-21): Use centralized configuration approach.
    let log_format = vlog::log_format_from_env();
    let _guard = vlog::ObservabilityBuilder::new()
        .with_log_format(log_format)
        .build();

    MainNodeBuilder::new()
        .add_pools_layer()?
        .add_fee_input_layer()?
        .add_object_store_layer()?
        .add_metadata_calculator_layer()?
        .add_state_keeper_layer()?
        .add_healthcheck_layer()?
        .build()
        .run()?;

    Ok(())
}