feat(aggregation_mode): save last processed block in a file

[JuArce]

Description

Current Behavior

Now, when the aggregation_mode starts, it fetches blocks using

# How far in the past should the service go to fetch batch logs
fetch_logs_from_secs_ago: 86400 # 24hs
# Anvil start with block time is 7 seconds
block_time_secs: 7

New Behavior

Instead of using time parameters, it should save to a file the latest processed block.

In the config config-proof-aggregator.yaml add a path to the file

The file should have the following yaml format

last_processed_block: <>

The aggregation_mode should read this file and fetches events from the last_processed_block to the current_block. Once the process finishes, the file should be updated

Note: The current_block is the block when the process starts, do not confuse with the block when the process finishes