Allow additional options when creating an external table

[timvw]

Is your feature request related to a problem or challenge? Please describe what you are trying to do.
CREATE EXTERNAL TABLE should allow for custom (table type specific options).

Eg: For CSV the has_header and delimiter option are available but it's not possible to add custom options but it's not possible to specify the timestamp for loading a delta/iceberg table.

In spark this is possible via the generic OPTIONS parameter.

Describe the solution you'd like
Extend datafusion such that these options can be provided

CREATE EXTERNAL TABLE magic 
STORED AS DELTALAKE 
OPTIONS ( at='1667827882' )
LOCATION 's3://mybucket/magic'

Describe alternatives you've considered
We could not support this

Additional context
Relates to #3867

[avantgardnerio]

@timvw I think this is an excellent idea. Syntactically it's in line with postgres' create external table and I think it allows for run-time extensibility that is required if we want to have a healthy ecosystem of 3rd party TableProviders .

[timvw]

Ok, currently the syntax is slightly different, but happy to change that ;)

current: [ OPTIONS ( option='value' [, ... ] ) ]
postgres: [ OPTIONS ( option 'value' [, ... ] ) ]

[timvw]

Updated the code to be the same as postgres..