This commit adds a :properties key to row parse result and a
`org-clock-csv--read-property' helper function to pull individual
properties out of it.

It turns out that `org-entry-properties' does *not* retrieve the
inherited properties by default, so this commit steps over all of
the buffer property keys and retrieves those properties manually,
as well.

Includes tests.

Co-authored-by: Shawn Martin-Truesdell <shawn@masyc.com>