SHDP-201 SHDP-202 SHDP-203 SHDP-204 SHDP-180 First changes for resource loader overhaul

Overhauling concepts around hdfs resource loader.
- Removed ChainedResourceLoader and modified HdfsResourceLoader to
extend DefaultResourceLoader. This allows to fall back to normal resource
resolving behaviour.
- New namespace handler for resource-loader-registrar which creates
bean for CustomResourceLoaderRegistrar.
- HadoopResourceLoaderParser is now parsing user attribute
- Added tests for namespace and other functional changes for
this commit.
- Tidy up, fixed some warning, javadocs, etc.
SHDP-201 SHDP-180 Fix tilde shortcut support
SHDP-205 SHDP-201 Fixing proper use of AntPathMatcher

Instead of doing custom path matching, rely on concepts from Spring
PathMatchingResourcePatternResolver order to have same matching
functionality.
SHDP-201 SHDP-180 tidy up
SHDP-207 Add option for resource loader not to process paths without prefix
SHDP-201 Fix isDirectory() not available for hadoop1
SHDP-201 Fix FileNotFoundException in resource loader

Moved getFileStatus(Path) after explicit exists(Path) call to
prevent exception to thrown. Modified tests to do checks
for paths which should exist and paths which should
not be present.
Merge remote branch 'jvalkeal/SHDP-201'
SHDP-201 Renaming the legacy HdfsResourceLoaderTest
SHDP-201 Adding script to ensure we have a /user directory with the expected permissions