DB: better handling of failed writes

[pdiakumis]

When you're in the process of writing 100+ tables for a single run and 1 of them has an issue, you don't want to re-write the already written tables. Or at least you want to be able to easily see which tables have/haven't been written for that run.
Perhaps keep a tracker table with nemo_id and nemo_table that get filled upon successful writes?

nemo_id	nemo_table	written
abc123	amber1	TRUE
abc123	amber2	TRUE
abc123	ppl1	FALSE
abc123	ppl2	FALSE
abc123	ppl3	FALSE