Fix timeout to default to 30 seconds instead of 30000 seconds

[Mytherin]

Found by @ywelsch

httplib splits the timeout into two components (sec and usec):

Server &set_write_timeout(time_t sec, time_t usec = 0);

We were passing the timeout into the seconds component:

client->set_write_timeout(http_params.timeout);

With a somewhat high default value of 30000. This fixes it so the default is 30 seconds.

[carlopi]

This depends on #7, that should make CI work properly on main, I will have CI pass / merge that one, then check CI here.

[Mytherin]

Looks like CI has gone through - @carlopi good to merge?