ENH: Simplify the steps to build remote modules.

Currently, two CMake swtiches are associated with each remote module.
Fetch_{module_name} is used to download the remote module into
the source tree, and then the Module_{module_name} will appear,
it takes another configuration to enable the module in the build
tree.

This commit removes the Fetch_{module_name} switch. Module_{module_name}
will be used to trigger the download and reconfiguration steps at once.

Change-Id: I5e3e3e8962a1657cf8995f61b21a8d6aa33c92ee
ENH: Turn remote module LSTK off by default.

In the updated version of LSTK repo,"EXCLUDE_FROM_ALL"
tag is added to the module dependency.Also the module name
no longer has ITK prefix in it.

Change-Id: Ia4467a0b2861a7e89e97028fe89d2ca61cb88c57
Merge topic 'LSTK'

cf265e5 ENH: Turn remote module LSTK off by default.
4ae1739 ENH: Simplify the steps to build remote modules.