JILS-5: Modularlise Code

On 2 Oct, a commit was made

- Started modularlising codebase View Commit

I think there's probably a lot more that can be done to tidy the codebase. Because it started with a fairly simple aim, I didn't necessarily exercise some of the discipline that I should have done in the coding style.

At some point, for the benefit of maintainability, it'll probably be worthwhile doing a full refactor, even if only to separate the CRUD from the views.

Commit 054ffe8 (https://github.com/bentasker/Jira-Issue-Listing/commit/054ffe885cbe9c007346bb435dbbf48ca3d68224) is a PoC for JILS-43, but starts the work of splitting out the CRUD.

Although, in the longer term, a better structure can probably be used, for the time being, the structure is being introduced so that code is split into

- queries
- templates

Where various templates (html/json) are available for the appropriate pages.

JILS-43 has done quite a lot of work in seperating the CRUD, however there's still a lot of general tidying to be done.

So far, the code has (as far as possible) simply been split into seperate files, so readability is still an issue, and the code is still fairly messy.

Need to finish moving files into the new structure (as some don't have a JSON equivalent, they weren't touched in JILS-43)

Bulk Change.

Clearing out old issues - it's unlikely I'll find time to do any further work on JILS.

New issues will be raised for relevant items if that proves not to be the case