IDOM URL slash safety

[Archmonger]

Current Situation

There are some portions of IDOM that currently do not automatically append/prepend forward slashes to URLs.

For example

• Assertion Error #741 (comment)

Proposed Actions

Look through any locations in the source where the user will input a URL.

Automatically append/prepend a forward slash when needed. In Python, an implementation may look like such:

f"/{ my_string.lstrip('/') }"

If a forward slash, or backwards slash, isn't expected in certain situations then we should also be stripping those.