Multihost support for High Availability setups

[porsager]

Multiple hosts can be specified like in psql.

It's either done through the connection string, or through arrays in the host and port parameters.

[porsager]

Would you mind taking a look at this @Minigugus and @stalniy ?

[Minigugus]

I haven't tested yet but looks good to me. I can try to test it this week if you want, but I never used the postgresql's multi hosts feature, I can't promise anything.

Do you want me to update typescript types by the way?

[porsager]

Thanks, a couple of extra eyes was fine, I've tested it ;)

Would be great to have the typescript types updated too 👍

[Minigugus]

I corrected some problems with the types along the way.

I also have an improvement for B but I wanted your opinion before committing, since it may be a breaking change. It improves support for multi-statement queries with unsafe. It's not a big deal, it doesn't deserve another PR I think, but it's off topic for this one. Should I push this anyway?

[porsager]

@Minigugus looks great, thank you - are any of the unrelated type changes breaking in any way?

re: unsafe Since it's unrelated, let's just take it in another PR