Convert contrib modules to use the extension facility.

This isn't fully tested as yet, in particular I'm not sure that the
"foo--unpackaged--1.0.sql" scripts are OK.  But it's time to get some
buildfarm cycles on it.

sepgsql is not converted to an extension, mainly because it seems to
require a very nonstandard installation process.

Dimitri Fontaine and Tom Lane

contrib/test_parser/test_parser--1.0.sql

@@ -0,0 +1,29 @@
+/* contrib/test_parser/test_parser--1.0.sql */
+
+CREATE OR REPLACE FUNCTION testprs_start(internal, int4)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE OR REPLACE FUNCTION testprs_getlexeme(internal, internal, internal)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE OR REPLACE FUNCTION testprs_end(internal)
+RETURNS void
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE OR REPLACE FUNCTION testprs_lextype(internal)
+RETURNS internal
+AS 'MODULE_PATHNAME'
+LANGUAGE C STRICT;
+
+CREATE TEXT SEARCH PARSER testparser (
+    START    = testprs_start,
+    GETTOKEN = testprs_getlexeme,
+    END      = testprs_end,
+    HEADLINE = pg_catalog.prsd_headline,
+    LEXTYPES = testprs_lextype
+);