CONPY-205: Added error constants

Error code constants are now defined in constants/ERR.
The file ERR.py is generated by helper/create_errconst.py
script, please don't edit it.

Author: 9EOR9

helper/create_errconst.py

@@ -0,0 +1,24 @@
+import requests
+
+ignore_definitions= ["ERR_ERROR_FIRST", "ER_ERROR_LAST", "CR_MIN_ERROR", "CR_MAX_ERROR",
+                     "CER_MIN_ERROR", "CER_MAX_ERROR", "CR_MYSQL_LAST_ERROR", "CR_MARIADB_LAST_ERROR"]
+
+files= ["https://raw.githubusercontent.com/mariadb-corporation/mariadb-connector-c/3.3/include/mysqld_error.h",
+        "https://raw.githubusercontent.com/mariadb-corporation/mariadb-connector-c/3.3/include/errmsg.h"]
+
+error_definitions= [] 
+
+for i in range(0, len(files)):
+  errors= requests.get(files[i], allow_redirects=True)
+  error_definitions+= errors.content.decode("utf8").split("\n")
+
+print("# Autogenerated file. Please do not edit!\n\n")
+
+for i in range(0, len(error_definitions)):
+  x= error_definitions[i].split(" ")
+  if len(x) == 3 and x[0] == "#define" and x[1] not in ignore_definitions and x[1][:9] != "ER_UNUSED":
+    try:
+      if int(x[2]) > 0:
+        print("%s = %s" % (x[1], x[2]))
+    except:
+      pass