This commit adds two new SQL Check Operators to the core sql.py file,
one called SQLColumnCheckOperator and one called SQLTableCheckOperator.
Corresponding tests are added as well. The current functionality of
these operators is minimal, but expected to grow over time. These
operators, unlike current ones, save information about the results
of the check queries that is then parseable by third party libraries.

Co-authored-by: Tzu-ping Chung <uranusjr@gmail.com>

Accidentally copied the last line of the file several times, this
commit remedies that change.

Improved the column check operator to include support for
greater than, geq, less than, and leq functions.
Updated logic and tests to reflect this change.

Improved the table check operator by refactoring
how checks are performed; this makes it much more customizeable
at the expense of knowing the specific result of checks, as
the results are now all just 0 or 1.

New docstrings were using example dictionaries in the param list,
and the way they were written before caused doc build errors. The
fix was to update the formatting and add missing words to the word list.

Moves record logging below the AirflowException for no records,
and makes the Exception message more clear.

Co-authored-by: Josh Fell <48934154+josh-fell@users.noreply.github.com>

SQLTableCheckOperator was rendering an invalid SQL query,
this fix changes the way the query template is built from the
passed in strings.

… result string

After some research, it seems the null_check query does *not* need
quotes around the column name.