Support date and time functions for new engine

[chloe-zh]

The date and time functions we are planning to support can be referring to MySQL Reference Manual. For those with implicit definitions or argument/return types, refer to BigQuery reference manual for DATE, DATETIME, TIME, and TIMESTAMP functions. For cases about null and missing values as the arguments, typically returns missing value if there is missing value in argument, else returns null if there is null value in argument, refer to AsterixDB for more details.

Work for each function includes:

• Function implementation in parser and runtime (please include the java docs when necessary)
• Unit test of implementation
• Comparison test that runs against ODFE-SQL, H2 and SQLite
• Documentation of user manual in corresponding category. Override legacy doc for functions existed in the old engine. Welcome to refer to / reuse the doc or appendix done here: https://github.com/chloe-zh/sql/blob/datetime/docs/user/dql/functions_categorical_draft.rst
• Examples with doctest

Example pull request: #713

Except the functions we have already implemented in our code, pending work includes: (click to check if the function is finished)

Prioritized:

• date
• time
• timestamp
• microsecond
• second
• minute
• hour
• day
• week
• month
• quarter
• year
• adddate
• date_add
• date_format
• date_sub
• dayname
• dayofweek
• dayofmonth
• dayofyear
• from_days
• monthname
• subdate
• time_to_sec
• to_days

---

• addtime
• convert_tz
• curdate
• current_date
• current_time
• current_timestamp
• curtime
• datediff
• extract
• from_unixtime
• get_format
• last_day
• localtime
• localtimestamp
• makedate
• maketime
• now
• period_add
• period_diff
• sec_to_time
• str_to_date
• subtime
• sysdate
• time_format
• timediff
• timestampadd
• timestampdiff
• to_seconds
• unix_timestamp
• utc_date
• utc_time
• utc_timestamp
• weekday
• weekofyear
• yearweek