Converted SQL mail into multiple files. (apache#1401)

Converted SQL mail into multiple files.

This pull request is aimed at improving the overall quality of our SQL codebase
by converting the main SQL (age-x.x.x.sql) file into multiple smaller files in the
sql directory. The primary goal is to enhance code readability, maintainability,
and organization for the benefit of the development team.

(cherry picked from commit f6e6af7)

.gitignore

@@ -1,6 +1,7 @@
 *.o
 *.so
 build.sh
+age--*.*.*.sql
 .idea
 .deps
 .DS_Store

Makefile

@@ -17,7 +17,7 @@
 
 MODULE_big = age
 
-
+age_sql = age--1.4.0.sql
 
 OBJS = src/backend/age.o \
        src/backend/catalog/ag_catalog.o \
@@ -75,7 +75,12 @@ OBJS = src/backend/age.o \
 
 EXTENSION = age
 
-DATA = age--1.4.0.sql
+#SQLS = $(sort ($(wildcard sql/*.sql)))
+SQLS := $(shell cat sql/sql_files)
+SQLS := $(addprefix sql/,$(SQLS)) 
+SQLS := $(addsuffix .sql,$(SQLS)) 
+
+DATA_built = $(age_sql)
 
 # sorted in dependency order
 REGRESS = scan \
@@ -110,7 +115,7 @@ ag_regress_dir = $(srcdir)/regress
 REGRESS_OPTS = --load-extension=age --inputdir=$(ag_regress_dir) --outputdir=$(ag_regress_dir) --temp-instance=$(ag_regress_dir)/instance --port=61958 --encoding=UTF-8 --temp-config $(ag_regress_dir)/age_regression.conf
 
 ag_regress_out = instance/ log/ results/ regression.*
-EXTRA_CLEAN = $(addprefix $(ag_regress_dir)/, $(ag_regress_out)) src/backend/parser/cypher_gram.c src/include/parser/cypher_gram_def.h src/include/parser/cypher_kwlist_d.h
+EXTRA_CLEAN = $(addprefix $(ag_regress_dir)/, $(ag_regress_out)) src/backend/parser/cypher_gram.c src/include/parser/cypher_gram_def.h src/include/parser/cypher_kwlist_d.h $(age_sql)
 
 GEN_KEYWORDLIST = $(PERL) -I ./tools/ ./tools/gen_keywordlist.pl
 GEN_KEYWORDLIST_DEPS = ./tools/gen_keywordlist.pl tools/PerfectHash.pm
@@ -134,6 +139,9 @@ src/backend/parser/cypher_gram.c: BISONFLAGS += --defines=src/include/parser/cyp
 src/backend/parser/cypher_parser.o: src/backend/parser/cypher_gram.c
 src/backend/parser/cypher_keywords.o: src/backend/parser/cypher_gram.c
 
+$(age_sql):
+	@cat $(SQLS) > $@
+
 src/backend/parser/ag_scanner.c: FLEX_NO_BACKUP=yes
 
 installcheck: export LC_COLLATE=C