Filename Change: prefer lower-case

[julie-ng]

Issue to gather changes for #47

Goal of Changes - Consistency and Less Git Conflicts

Mixed filename cases, i.e. CamelCase can cause problems, esp. broken links. When working in a multi-OS open source project, it's better practice to use lowercase with dashes, i.e. kebab-case.

As people work with IDE plugins, "best practice" changes can be made that result in obscure merge conflicts that we challenging for people new to git to resolve. Goal is to standardize and introduce a CI check.

Changes To Be Made

• No content changes will be made.
• Only file renames, e.g. EndToEnd.md --> end-to-end.md
• And updated links in the files to refer to kebab-case version.