Enable the configuring of the default precision for timestamp/datetime fields

[fabis94]

Feature discussion / request

It's super annoying that Postgres stores high-precision timestamps, while JS can't even read them and ends up truncating the timestamp when it enters JS land, causing weird bugs later on when it comes to filtering & sorting.

Additionally, it doesn't appear that the latest version of Knex (2.2.0) allows projects using it to configure the default precision for timestamp/datetime fields. If this were possible, then we could just configure all new tables to use a lower precision value for all timestamp/datetime fields by default, without devs having to remember to set the correct precision.

So the request is - Please add a way to configure the default timestamp/datetime precision level.

[fabis94]

If it's unlikely for this to be addressed any time soon, I'm open to doing a PR for this, as long as I get some pointers about how this should be structured (just so I don't have to re-do it)

[fabis94]

I've added this feature myself (with integration tests): #5311

[ianchanning]

Until that gets approved, for the unfortunate souls that find their way here wondering why their pagination is failing, try using date_trunc('milliseconds', field).