Move sql store code into store/sqlstore package (#7502)

* move sql store code into store/sqlstore package

* move non-sql constants back up to store

* fix api test

* derp

Makefile

@@ -349,7 +349,7 @@ test-postgres:
 	@sed -i'' -e 's|"DriverName": "mysql"|"DriverName": "postgres"|g' config/config.json
 	@sed -i'' -e 's|"DataSource": "mmuser:mostest@tcp(dockerhost:3306)/mattermost_test?charset=utf8mb4,utf8"|"DataSource": "postgres://mmuser:mostest@dockerhost:5432?sslmode=disable"|g' config/config.json
 
-	$(GO) test $(GOFLAGS) -run=$(TESTS) -test.v -test.timeout=2000s -covermode=count -coverprofile=cprofile.out -coverpkg=$(ALL_PACKAGES_COMMA) github.com/mattermost/mattermost-server/store || exit 1; \
+	$(GO) test $(GOFLAGS) -run=$(TESTS) -test.v -test.timeout=2000s -covermode=count -coverprofile=cprofile.out -coverpkg=$(ALL_PACKAGES_COMMA) github.com/mattermost/mattermost-server/store/sqlstore || exit 1; \
 	if [ -f cprofile.out ]; then \
 		tail -n +2 cprofile.out >> cover.out; \
 		rm cprofile.out; \