[request] add sub_tx_id to various sector-level spells

[jeff-dude]

initiated in #5392 to add new column in tokens_<blockchain>.transfers spells to include a distinct id for each transfer.

requirements:

• non-null set of unique columns to use in downstream spells
  • for example, in transfers, spells currently use a surrogate key to bypass nulls which DBT doesn't like in merge statements:

    -- We have to create this unique key because evt_index and trace_address can be null
    {{dbt_utils.generate_surrogate_key(['t.block_number', 'tx.index', 't.evt_index', "array_join(t.trace_address, ',')"])}} as unique_key
    

current approach in nft.trades:

• combine both evt_index and trace_address into sub_tx_id, use sub_tx_id as part of unique key set along with tx_hash and other standard columns
• to deal with possible collisions, use arbitrary addition to row_number output (more info here)

decision point:

• unique_key vs. combo of tx_hash and sub_tx_id
  • where unique_key is a random hash on top of fields to create a random surrogate key that has no meaning outside of backend ETL processing
  • where tx_hash is from raw data, sub_tx_id is built to compliment tx_hash to make rows unique

initial thoughts:

• personally, i have no strong opinion to keep unique_key -- this was simply a solution to avoid nulls in PK values and an out-of-box solution from DBT
• if sub_tx_id provides more value than just backend ETL processing, such as simplified testing and analysis downstream in queries, then i'm all for it

spellbook-wide impact:

• as mentioned in original PR, this would be beneficial to apply universally to all sector-level spells. for example, any spell lineages in the models/_sector/ directory
  • it's fine to start with the big ones: dex/nft/token_transfers

edit:
before we start any work, let's get on the same page here. then we can track changes to each sector.