Support for IBM037 and IBM1140?

[jbowtie]

By my count there are four EBCDIC code pages likely to be encountered on the internet, though the comprehensive list of all registered IANA character sets found at https://www.iana.org/assignments/character-sets/character-sets.xhtml lists about 20 EBCDIC codepages.

Most of them are cross-referenced to the code page definitions in https://datatracker.ietf.org/doc/html/rfc1345 (which aggregates many of the original sources into a single reference document).

I'm happy to do this work for the two most common pages (IBM037 and IBM1140) as I am implementing an XML parser, however I don't know if it's something you would want in scope, behind a cargo feature, or segregated into an EBCDIC-specific crate.