Improve PCML to allow non-integer return variables and SQL service to retrieve PCML

Please update PCML to allow any return variable or parameter that RPG natively supports and add a SQL service to pull PCML from the object. This was mentioned in a comment for IBMI-I-2812 but I thought it warranted it's own request. The PGMINFO control option would need an extra option to enable full features so it doesn't impact current Java usage. Additionally please add what source file and line number data structures and procedures were defined in.

This would be a huge help to automate building web application interfaces that use the IBM i XMLSERVICE to interface with RPG. Right now you have to manually build your own interface but being able to fully take advantage of PCML to create interfaces programmatically would greatly simplify the process. The SQL service would make it much easier to write a PHP, NodeJS, etc program to pull PCML out and create interfaces from the information.

Also this would help requests like IBMI-I-59 as a data source to build documentation from that doesn't require a custom language parser. Ie if PCML could additionally be allowed to export documentation notations that would be awesome. For example if the preceding comments had a docblock (see https://en.wikipedia.org/wiki/Docblock) the compiler could extract that into a super extended PCML definition.

If all of these requests are allowed for, perhaps the compiler should be able to produce multiple PCML exports - ie one that is Java compatible, one that is full variable/parameter information, and one with the extra docblock information. For example on a procedure declaration (dcl-proc) the PGMINFO might have an option to exclude it from Java compatible PCML but include it in the full feature PCML. Also non-exported procedures might have an option to only have them appear as private in the documentation PCML.

Even if the PCML could not be extended to include doc block information with the source file & line number each data structure & procedure were defined in we could more easily write a program to retrieve that information ourselves.