pgsql: Cleanup code in reloptions.h regarding reloption handling

Cleanup code in reloptions.h regarding reloption handling

reloptions.h includes since ba748f7 a set of macros to handle reloption
types in a way similar to how parseRelOptions() works. They have never
been used in the core code, and we have more simple methods now to parse
and fill in rd_options for a given relation depending on its relkind, so
remove this interface to simplify things.

Per discussion between Amit Langote, Álvaro Herrera and me.

Discussion: https://postgr.es/m/CA+HiwqE6zbNO92az6pp5GiTw4tr-9rfCE0t84whQSP+YwSKjMQ@mail.gmail.com

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/50d22de9325f41a32faeb0d1055f50b43d0507b3

Modified Files
--------------
src/backend/access/common/reloptions.c | 15 +++-
src/include/access/reloptions.h | 126 ++-------------------------------
2 files changed, 17 insertions(+), 124 deletions(-)