pgsql: Rework option set of oid2name

Rework option set of oid2name

oid2name has done little effort to keep an interface consistent with
other binary utilities:
- -H was used instead of -h/-host. This option is now marked as
deprecated, still its output is accepted to be backward-compatible.
- -P has been removed from the code, and was still documented.
- All options gain long aliases, making connection options more similar
to other binaries.
- Document environment variables which could be used: PGHOST, PGPORT and
PGUSER.

A basic set of TAP tests is added on the way, and documentation is
cleaned up to be more consistent with other things.

Author: Tatsuro Yamada
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/c7e7f25c-1747-cd0f-9335-390bc97b2db5@lab.ntt.co.jp

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/1aaf532deabfa356c99abc80fc78d988ad1f1355

Modified Files
--------------
contrib/oid2name/.gitignore | 2 +
contrib/oid2name/Makefile | 6 +++
contrib/oid2name/oid2name.c | 114 +++++++++++++++++++++++-----------------
contrib/oid2name/t/001_basic.pl | 12 +++++
doc/src/sgml/oid2name.sgml | 81 ++++++++++++++++++++--------
5 files changed, 146 insertions(+), 69 deletions(-)