WIP Support for ?params=target|scope|format input, replacing apache rewrites

[mberkowski]

We need to eliminate an Apache web server mod_rewrite dependency whereby apache accepts ?params=targetval|scopeval|formatval expanding into Janus ?target=targetval&scope=scopeval&format=formatval

This will add native support for the pipe-delimited params= parameter

Implementation notes:

• For compatibility with how it works under mod_rewrite, if BOTH a params= string and other individual Janus parameters are present, the individual parameters are discarded/overwritten by the delimited params= string
• In code, they will be literally overwritten. Janus params are parsed & populated first, then delimited params= is expanded, overwriting them including nulling them out if they were empty in the delimited string.

Target completion/merge: Spring 2025.