Create a crate to parse bridges pool assignments files

The bridge distribution service BridgeDB publishes bridge pool assignments describing which bridges it has assigned to which distribution pool. BridgeDB receives bridge network statuses from the bridge authority, assigns these bridges to persistent distribution rings, and hands them out to bridge users. BridgeDB periodically dumps the list of running bridges with information about the rings, subrings, and file buckets to which they are assigned to a local file. The sanitized versions of these lists containing SHA-1 hashes of bridge fingerprints instead of the original fingerprints are available for statistical analysis.

Create a crate to parse bridge pool assignments files and store them in a Database and/or in tabular format as csv or parquet files.

References:

https://metrics.torproject.org/collector.html#bridge-pool-assignments

https://gitlab.torproject.org/tpo/network-health/metrics/library/-/blob/master/src/main/java/org/torproject/descriptor/BridgePoolAssignment.java?ref_type=heads

DB Schema to save bridge pool assignments: https://gitlab.torproject.org/tpo/network-health/metrics/metrics-sql-tables/-/blob/main/bridge_pool_assignment_tables.sql?ref_type=heads