get a relations DDL server-side

I would like to introduce the ability to get object DDL (server-side) by introducing a new function with roughly the
followingprototype:
 

get_ddl(regclass)
RETURNS text
LANGUAGE C STRICT PARALLEL SAFE;

A previous conversation seemed to encourage the development of this feature

https://www.postgresql.org/message-id/CADkLM=fxfsrHASKk_bY_A4uomJ1Te5MfGgD_rwwQfV8wP68ewg@mail.gmail.com

I would like to start work on this patch but wanted acceptance on the function signature. 

Thank you!