Adding HOT str_replace and get_resource functions

This patch adds support for two functions, get_resource and str_replace to HOT
to enable the definition of new HOT samples. Especially str_replace aims to
simplify the definition of scripts in HOT templates.

Change-Id: Ic14fee36bdc0b9c5d79ade7ece5fa1b5331c864a
Merge "Adding HOT str_replace and get_resource functions"