Add DevContainer

[ross-p-smith]

Purpose

This adds the ability to run this solution in a vscode Dev Container. It will install python 3, azure cli, Functions Core Tools and bicep automatically once opening

Does this introduce a breaking change?

[ ] Yes
[x] No

Pull Request Type

[ ] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[x] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:

How to Test

• Install "Remote Development" extension in vscode.
• Clone repo in WSL
• Open in vscode and follow prompt to "Open in Development Container"
• Profit!

What to Check

Verify that the following are valid by running them in your dev container terminal.
func --version
bicep --version
az --version
python --version

Other Information

This is the first PR. I will add the other developer build steps if you think this is a benefit. Related to #69