Add support for EC2 config scripts

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

Change-Id: Ic9b2c73838c606d3eeaf039363dbdf46313379ca
Fix tests mocking bug when doing regex search

Change-Id: I7a6d8b5e111884e2c3017df82bc447ba4e99905c