Add kolide_softwareupdate table

[RebeccaMahany]

Closes #1122.

Adds a new execparser table to run softwareupdate --list to return recommended updates for macOS.

Sample query and output:

osquery> select * from kolide_softwareupdate;
+---------------+--------+-------------+-----------------------------+-------+
| fullkey       | parent | key         | value                       | query |
+---------------+--------+-------------+-----------------------------+-------+
| 0/Label       | 0      | Label       | macOS Ventura 13.3.1-22E261 | *     |
| 0/Recommended | 0      | Recommended | YES                         | *     |
| 0/Size        | 0      | Size        | 868648KiB                   | *     |
| 0/Title       | 0      | Title       | macOS Ventura 13.3.1        | *     |
| 0/Version     | 0      | Version     | 13.3.1                      | *     |
| 0/Action      | 0      | Action      | restart                     | *     |
+---------------+--------+-------------+-----------------------------+-------+

[directionless]

I would take this.

Error handling is okay -- the thing that calls this will continue on error.

I'm not sure you need to split softwareupdate.go from parse.go. And parseUpdate feels a little weird. But it's simple ebough

[directionless]

Probably not worth changing, but given the number of these I'd probably not embed, and instead make something like readTestFile(t, filename) []byte and stick that into the table definition