fix: sql fn params

[psteinroe]

the idea is to replace the fn params with a default value based on their type:

create or replace function users.select_no_ref (user_id int4) returns table (
    first_name text
) language sql security invoker as $$
select
    first_name
FROM 
    users_hidden.users
where 
    id = user_id;
$$;

will become

create or replace function users.select_no_ref (user_id int4) returns table (
    first_name text
) language sql security invoker as $$
select
    first_name
FROM 
    users_hidden.users
where 
    id = 0; -- <-- here
$$;

Todo

• [ ] pass params to typechecker
• [ ] implement apply_identifiers

fixes #353 fixes #352