Create XML-RPC or SOAP interface for Intellij plugin

Mark Derricutt has created an intellij plugin. We should provide him with more access to JIRA via a remote API.

Here is his list of suggested things to implement:

1. Access to jira installation metadata.
1.1 List of available projects to the user, in rss, with items for
project name, description, lead developer, project id, etc. etc.
1.2 List of available resolutions, issue types, issue status', and other
lookup information, also in rss.
1.3 Admin metadata, admin email details/names/urls in rss.
1.4 User access to Jelly ( limited tags, access restricted ). For
editing/updating/commenting issues, I'm currently looking at just doing
HTTP push/form submission, but the URL wrangling is a kinda messy
approach, esp. when theres Jelly sitting there. I've used it before in
a simple Jira Log4j appender, but it requires the user to have admin
access.