ChainMetadataAggregator Integration

[dioptx]

This is the first PR for the Total Crypto metadata integration. It provides the appropriate structure to base further additions and allows for smaller follow up PRs.

Additions:

• Created pipeline: build_all_chains_metadata() with 7 processing steps
• Dagster asset: all_chains_metadata_asset with config schema
• Config fields: output_bq_table, manual_mappings_filepath, bq_project_id, bq_dataset_id
• CLI command: build-metadata under opdata chains
• Registered Dagster asset module in defs.py

[MSilb7]

Made one comment about maybe writing out what each step is supposed to do, so we can align on that before writing code.

otherwise, agree on a modular-type approach & the data sources go through a few steps before we create the massive joined dataset