Date objects encoding is broken

[lbeschastny]

Here is how Date objects are encoded right now:

if (v instanceof Date) return ('' + v.valueOf()).substr(0, 10)

This code has two problems.

First, it expects timestamp to have exactly 13 digits, which is wrong:

> ('' + new Date('2000-01-01').valueOf()).substr(0, 10)
'9466848000'
> ('' + new Date('2022-01-01').valueOf()).substr(0, 10)
'1640995200'

Second, it sends timestamps as strings which only works with DateTime type, but not with Date:

SELECT
    toDateTime(1661353838),
    toDate(1661353838),
    toDateTime('1661353838'),
    toDate('1661353838')

┌─toDateTime(1661353838)─┬─toDate(1661353838)─┬─toDateTime('1661353838')─┬─toDate('1661353838')─┐
│    2022-08-24 18:10:38 │         2022-08-24 │      2022-08-24 18:10:38 │           1970-01-01 │
└────────────────────────┴────────────────────┴──────────────────────────┴──────────────────────┘