Fix dates being initialized with client timezone when using timestamps

[AppelBoomHD]

Timestamps in mysql and postgressql are by default save as UTC timestamps.
Javascripts Date initializer assumes that dates are written in the client's timezone, when no explicit timezone is given in the initializer. This PR manually adds the UTC timezone to the initializer string.

Another way to this is (https://stackoverflow.com/a/3075893/13799537):

// Split timestamp into [ Y, M, D, h, m, s ]
var t = "2010-06-09 13:12:01".split(/[- :]/);

// Apply each element to the Date function
var d = new Date(Date.UTC(t[0], t[1]-1, t[2], t[3], t[4], t[5]));
return new Date(d);

In TypeScript this gives a couple type-errors, which is why I chose the more simple one-liner solution.

[dankochetov]

Honestly, I'm not sure if there are hidden implications of adding this. Could you add an integration test for this behavior?

[AppelBoomHD]

I'm not very familiar with unit testing, but I think I got it working correctly.
Added a test for mysql and postgres databases to test whether the timestamp received from the database is converted to the correct timezone. The test for mysql fails before my change and passes after applying the change.
I realized postgres automatically converts the timestamp to the correct timezone, so I reverted the change related to postgres timestamps.

[dankochetov]

Could you add a test inserting a Date with a non-default timezone specified? I'm curious if it'll change the date string format returned from the driver on selection.

[AppelBoomHD]

Good point! I added the test as you specified for both mysql and postgres timestamps. Upon running the tests I found out that timestamps are by default inserted respecting the client's timezone as well, instead of in UTC format. I pushed a fix for this behavior, which passed all the tests.

[dankochetov]

Seems like you have a code formatter (Prettier, probably) enabled on save, which changed the formatting quite a bit. We use Dprint for this repo, so please re-format the files with it (it might not rollback some formatting you already did, so you'll have to change it back manually).

[dankochetov]

@AppelBoomHD please resolve the merge conflicts