cli/sql: time-related types often display extraneous info

[solongordon]

pq represents all time-related types (DATE, TIME, TIMESTAMP, TIMESTAMPTZ) using Go's time.Time. As a result, cockroach sql often uses too much precision when it displays these types. This is only a display bug but it can be confusing for users.

The most egregious example is TIME, where we display an irrelevant date and timezone.

root@:26257/> select '02:03:04'::TIME;
+---------------------------+
|     '02:03:04'::TIME      |
+---------------------------+
| 0000-01-01 02:03:04+00:00 |
+---------------------------+

But DATE and TIMESTAMP are also somewhat misleading.

root@:26257/> select '2018-01-10'::DATE;  -- should not include time
+---------------------------+
|    '2018-01-10'::DATE     |
+---------------------------+
| 2018-01-10 00:00:00+00:00 |
+---------------------------+

root@:26257/> select '2018-01-10 02:03:04'::TIMESTAMP;  -- should not include timezone
+----------------------------------+
| '2018-01-10 02:03:04'::TIMESTAMP |
+----------------------------------+
| 2018-01-10 02:03:04+00:00        |
+----------------------------------+

[otan]

related to #44548, i think this results in real bugs when using things such as client dumps.

[knz]

Fixed in #62310.