Bug 2057235 - Remove XMLRPC API support

[Xzzz]

Summary

Removes xmlrpc.cgi and Bugzilla/WebService/Server/XMLRPC.pm as well as support for the USAGE_MODE_XMLRPC and ERROR_MODE_DIE_SOAP_FAULT modes, the dependencies of the xmlrpc feature (SOAP::Lite, XMLRPC::Lite), the xmlrpc_* error codes and obsolete XML-RPC references in docs/POD.

This is the first of a small set of child bugs cleaning up the old API surface, see 1599274 for details.

Changes

Deleted

• xmlrpc.cgi - the XML-RPC entry-point script
• Bugzilla/WebService/Server/XMLRPC.pm - the XML-RPC server implementation

Core dispatch/constants

• Bugzilla.pm - removed the USAGE_MODE_XMLRPC branch in usage_mode(), removed xmlrpc.cgi script-name detection and updated POD examples
• Bugzilla/Constants.pm - removed the USAGE_MODE_XMLRPC and ERROR_MODE_DIE_SOAP_FAULT constants and their exports
• Bugzilla/Util.pm - removed the XML-RPC check from i_am_webservice() and updated POD
• Bugzilla/Error.pm - removed the ERROR_MODE_DIE_SOAP_FAULT branch

WebService layer

• Bugzilla/WebService/Bug.pm - simplified count_only handling (dead XML-RPC branch removed)
• Bugzilla/WebService/Constants.pm - removed xmlrpc_invalid_value/xmlrpc_illegal_content_type error codes and the now-unused XMLRPC_CONTENT_TYPE_WHITELIST constant
• Bugzilla/WebService.pm, Bugzilla/WebService/Server.pm, Bugzilla/WebService/Server/JSONRPC.pm, Bugzilla/WebService/Server/REST.pm - removed stale XML-RPC references from POD and comments (JSONRPC's POD now points to REST as the stable alternative)
• Bugzilla/WebService/{Bugzilla,BugUserLastVisit,Classification,Group,Product,User}.pm, extensions/Review/lib/WebService.pm - removed XML-RPC references from POD

Dependencies

• Makefile.PL - removed the xmlrpc optional-feature block (SOAP::Lite, XMLRPC::Lite, Test::Taint requirement)
• Bugzilla/Install/Requirements.pm - removed the xmlrpc entry from FEATURE_FILES (used by t/001compile.t)
• cpanfile - removed the unconditional SOAP::Lite and XMLRPC::Lite requires

Templates

• template/en/default/global/user-error.html.tmpl - removed the two XML-RPC-only error message blocks
• template/en/default/admin/params/admin.html.tmpl - removed "XML-RPC" from a param description

Test plan

• prove t/001compile.t
• Confirm REST/JSON-RPC API still functions (manual test or QA suite from bug 1619459)
• Confirm xmlrpc.cgi now 404s

Reference

• Bugzilla link: 2057235
• Part of 1599274