ZAP scanner: Cut the URL elements to the maximum size they can actually have

[ptrovatelli]

When the endpoint URL is very big, the parser fails with:

Traceback (most recent call last):
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/utils.py", line 84, in _execute
    return self.cursor.execute(sql, params)
  File "/usr/local/lib/python3.5/site-packages/django/db/backends/mysql/base.py", line 71, in execute
    return self.cursor.execute(query, args)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 206, in execute
    res = self._query(query)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/cursors.py", line 312, in _query
    db.query(q)
  File "/usr/local/lib/python3.5/site-packages/MySQLdb/connections.py", line 224, in query
    _mysql.connection.query(self, query)
MySQLdb._exceptions.DataError: (1406, "Data too long for column 'query' at row 1")

this cuts the size of the field to the actual field length in the DB