Geolocation: Core Capability Preview

This commit adds res_geolocation which creates the core capabilities
to manipulate Geolocation information on SIP INVITEs.

An upcoming commit will add res_pjsip_geolocation which will
allow the capabilities to be used with the pjsip channel driver.

This commit message is intentionally short because this isn't
a simple capability.  See the documentation at
https://wiki.asterisk.org/wiki/display/AST/Geolocation
for more information.

THE CAPABILITIES IMPLEMENTED HERE MAY CHANGE BASED ON
USER FEEDBACK!

ASTERISK-30127

Change-Id: Ibfde963121b1ecf57fd98ee7060c4f0808416303

res/res_geolocation/geoloc_common.c

@@ -0,0 +1,36 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2022, Sangoma Technologies Corporation
+ *
+ * George Joseph <gjoseph@sangoma.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+#include "asterisk.h"
+#include "geoloc_private.h"
+
+static const char *result_names[] = {
+	"Success",
+	"Missing type",
+	"Invalid shape type",
+	"Invalid variable name",
+	"Not enough variables",
+	"Too many variables",
+	"Invalid variable value"
+};
+
+const char *ast_geoloc_validate_result_to_str(enum ast_geoloc_validate_result result)
+{
+	return result_names[result];
+}
+