Update `dbi-open` to use modern URI formats

[linas]

The dbi-open call should be updated to accept the modern connection URI's. For example:

;  generic
postgresql://[user[:password]@][netloc][:port][,...][/dbname][?paramspec]
; for SSL:
postgresql://user:pass@host:5432/db?sslmode=require
; for unix sockets:
postgresql:///dbname?host=/var/run/postgresql
; for localhost:
postgresql://localhost

See https://www.postgresql.org/docs/current/libpq-connect.html#LIBPQ-CONNSTRING for details.

The other dbs -- mysql and sqlite3 do something similar.

@NalaGinrut -- maybe this would be interesting to you?

[NalaGinrut]

@linas It's not easy to make a unified API, execution path, and message contract among all three DBDs. We have managed to make it work smoothly so far. I'll have an article on the experiences about it. And I'll leave modern URI to future contributors.

[NalaGinrut]

BTW, we're a small team driven by the commercial cases to patch guile-dbi for products. Currently, we have less motivation to patch the URI way. We may consider patching that if there are related commercial cases. Our customers have no interest at present.

[linas]

Ah. OK. Are you using any coding agents? Claude? Codex? These agents work really well, as long as you are very precise with what you want, and carefully monitor the code changes. For me, it saves a lot of time; they do the boring, tedious changes. The only downside so far is that my brain melts while I wait for them to finish. And, of course, dealing with the garbage that they invariably generate.

[NalaGinrut]

Yes, but frankly, AI can only cover 80% works. I've spent several hours cleaning their shit in code. However, it's still saving a lot of time. The only caveat is that it sometimes feels irritating.