Allow SAML authentication process for deep URLs

[bcolas]

Using Spring Saved Request, through PentahoSamlAuthenticationSuccessHandler, redirection is made after authentication process to the initial URL asked by 'user'

[wingman-pentaho]

Hello, This is an automated comment from our build system. Since this pull request originated from a user not in the Pentaho organization, we will not proceed with automatic validation of the pull request. However, rest assured that it will be reviewed manually as soon as we get the chance. Thanks for your contribution!

[pedrofvteixeira]

Hi @bcolas ,

first of all, my apologies for the delayed review, as only now I had a chance to review it.
I would also like to thank you for your contribution to the Pentaho SAML sample.

To ease the process of reviewing/processing this PR, there are a couple to things I would ask of you, if possible:

• Squash your commits into a single one; doing so eases traceability and potential cherry-picking into other branches ( once processed ).
• The change made at the filterChainProxy of applicationContext-spring-security-saml.xml will henceforth affect any and all deep URLs, for anyone using it.
  • A less impactful change can be made by, for example, keeping the current spring filterChainProxy block as-is, and adding next to it a commented-out block that holds these changes
    • properly accompanied by a comment section stating something like "uncomment the following block below to allow SAML to also operate against deep URLs ( commenting out the default xml block above )"
• If you are going to update the artifacts versioning please do so by pointing to the latest 6.1, which is 6.1.0.19.384
  • This can, at any time, also be done automagically by anyone, by use of the mvn release:update-versions flag

Again, thank you for your contribution to the Pentaho SAML sample.

CC'ing @pamval , @dkincade , @mbatchelor