Fix support for CloudStack metadata

* Remove unused methods
* Add support for multiple public keys

Change-Id: I0d19fef4ea354c05f29b9fe8ef4ea19ddd3b2bba
Fix tests mocking bug when doing regex search

Change-Id: I7a6d8b5e111884e2c3017df82bc447ba4e99905c
Add support for EC2 config scripts

The userdatautils plugin now supports EC2 formatted scripts.
It consists of multiple batch or powershell scripts enclosed
into specific tags, where the batch part is executed before
the powershell one.

Change-Id: Ic9b2c73838c606d3eeaf039363dbdf46313379ca