Added utils library initialization function and improved replace_quoted

Currently the initialization function only prepares PCRE2 patterns for use.
Added the call to the new utils_init() function to MaxScale and all relevant
tests.

The replace_quoted now uses a shared PCRE2 pattern which should remove some
of the overhead of the function.

utils/skygw_utils.h

@@ -158,6 +158,8 @@ struct skygw_file_st {
 
 EXTERN_C_BLOCK_BEGIN
 
+bool utils_init(); /*< Call this first before using any other function */
+void utils_end();
 slist_cursor_t* slist_init(void);
 void slist_done(slist_cursor_t* c);
 size_t slist_size(slist_cursor_t* c);