Preloader architecture, memory, and other improvements

[xadahiya]

FEAT: Modular preloader architecture with memory and other improvements

Checklist

• My branch is up-to-date with upstream/develop branch.
• Everything works and tested for Python 3.8.0 and above.
• I ran pre-commit checks against my changes.

Change logs

• Cleaner and Resilient Preloader Architecture to support generic preloading for projects
• Refactoring and project structure improvements
• Memory Optimizations
• 7d aggregate calculation fixes
• Other minor performance and documentation improvements

Preloader Config

{
    "preloaders": [
        {
          "task_type": "block_transactions",
          "module": "snapshotter.utils.preloaders.tx_receipts.preloader",
          "class_name": "TxPreloadWorker"
        },
        {
          "task_type": "block_details",
          "module": "snapshotter.utils.preloaders.block_details.preloader",
          "class_name": "BlockDetailsPreloader"
        },
        {
          "task_type": "eth_price",
          "module": "snapshotter.utils.preloaders.eth_price.preloader",
          "class_name": "EthPricePreloader"
        }
    ],
    "delegate_tasks": [
        {
          "task_type": "txreceipt",
          "module": "snapshotter.utils.preloaders.tx_receipts.delegated_worker.tx_receipts",
          "class_name": "TxReceiptProcessor"
        }
    ],
    "timeout": 60
}

Projects Config changes for each project type

       "preload_tasks":[
           "block_transactions"
      ],

[SwaroopH]

LGTM! Tested on 2 different machines.