Performance improvements

[Glandos]

It changes the SQL a lot, but I kept all existing checks

• don't query files torrents are not inserted
• use basic types as much as possible (no strftime, hex)
• run sqlite in batch instead of window

Here are my results, ran on AMD Ryzen Pro 4750G + 16GB RAM on SSD, with a 29 millions magnetico database. Arguments list: --source-name magnetico --add-files --add-files-limit 200 --insert-content

• On an empty postgresql target: from 260 it/s to 980 it/s
• On an already filled postgreql target (so a lot of conflicts): from 260 it/s (unchanged) to 6000 it/s

So it's a huge win for pre-filled postgresql target, since this will never query.

Please double check that I didn't miss something.
I didn't added #10 in this, but I ran my tests with it.

[Glandos]

I've added support for pgcopy.

The code is somewhat more complicated, but performance are nearly doubled.
The only missing bit is insertion in torrent_contents because it uses a tsvector which is not supported by pgcopy. Not yet: altaurog/pgcopy#47

[Glandos]

Using pgcopy for file insertion removed the detection of duplicated file that are all empty. I don't know if I can restore that easily, since it's done in a generator.

[Glandos]

Target DB status	main output	pg_perf output
empty	2282/29000001 [00:30<107:59:03, 74.59it/s]	58000/29000001 [00:30<4:15:12, 1890.13it/s]
full	9811/29000001 [00:30<25:05:19, 320.97it/s]	226000/29000001 [00:30<1:05:05, 7367.77it/s]

"empty" is a database without any entries. "full" is the database with all entries existing. This is useful for re-importing entries with only a few changes, e.g. merging divergent data.

The benchmark was run with:

find ./bitmagnet/base/ -type f -exec dd if={} iflag=nocache count=0 status=none \; && systemctl restart postgresql@17-bitmagnet
dd if=./database.sqlite3 iflag=nocache count=0; uv run --with 'pgcopy @ https://github.com/Glandos/pgcopy/archive/refs/heads/tsvector.zip' --with 'tqdm' magnetico2database.py --dbname bitmagnet_full --user bitmagnet --password 'XXX' --host localhost --port 5433 --source-name magnetico --add-files --add-files-limit 200 --insert-content ./database.sqlite3

• dd is useful to evict file cache.
• pgcopy is my own branch, waiting for merging
• I replaced bitmagnet_full with bitmagnet_empty as dbname for the other test.