Single function for parsing timestamps/dates

Today, if you want to parse a date or timestamp, you have to use the unix time function and then cast to a timestamp. Its a little odd there isn't a single function that does both. I propose we add

to_date(<input>, <pattern>)/to_timestamp(<input>, <pattern>).

For reference, in other systems there are:

MS SQL: convert(<input>, <pattern id>). See: https://technet.microsoft.com/en-us/library/ms174450(v=sql.110).aspx
Netezza: to_timestamp(<input>, <pattern>). See: https://www.ibm.com/support/knowledgecenter/SSULQD_7.0.3/com.ibm.nz.dbu.doc/r_dbuser_ntz_sql_extns_conversion_funcs.html
Teradata has special casting functionality: cast(<input> as timestamp format '<pattern>')
MySql: STR_TO_DATE(<input>, <pattern>). This returns a datetime when you define both date and time parts. See: https://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html