Sanitization and password

[jbenito]

Several issues:

1. In base.py sanitization is happening after checkParams. So, if the developer gets the value into a variable in checkParams and uses it afterwards, sanitization would be useless (for case in which SanitizationLevel?=0)
2. There is a variable in RH which is _doNotSanitizeFields that we can use to avoid some params (password) to be sanitize. Services does not implement it! it should be consistent.
3. Once we move all the services to rest, make sure that we do not sanitize "accessKey" and "modifyKey"