Added fix and logic for xmx and xms attribute values for agent

The xmx denotes the maximum value for virtual memory allocation the JVM while the xms denotes the initial value. In the attributes for agent it was declared the othe way around, e.g. xms as the maximum and xmx as the initial. This would break the agent in cases where the cloud server has more RAM (e.g. 4GB). I also added some logic to protect against cases where the maximum would be set lower than the initial (e.g. when the server has 1GB of RAM).