Fix the Weblogic travis build and remove dead code

This commit adds support for Weblogic and Oracle JREs to be downloaded during
testing from an externally configured URI. The codebase itself can not
download these products and contains no reference to any valid download
locations. The locations can be configured with environment variables
'WEBLOGIC_DOWNLOAD' and 'ORACLE_JRE_DOWNLOAD'. Other fixes include changes to
the timeouts used in the download_cache tests. Two undocumented methods in the
Weblogic component have been documented. Container Utils removed as it is
unused and has been removed from the upstream java_buildpack code.

[#80731808]