Updated sections covering heap size and Liferay shared libraries.

[peerkar]

Hi!

Suggesting two changes to the DXP on WebSphere deployment article:

1. Setting heap size through administrative UI instead of editing configuration XMLs directly. I think avoiding manual XML editing should be avoided when possible.
2. Adding a note of alternative option for portal dependencies location. This was asked by a customer who found putting the libraries in a WebSphere's global classpath folder as a not viable option.

What do you think?