feat: implement scenario 5

[sinedied]

Sorry for the huge PR, here's a summary of the changes:

• Added stripe service (container app)
• Added payments/reservations view in profile page in portal
• Added all-in-one script for creating and deploying a new env and setting up local dev
• Added complete APIM setup for Function app and Stripe Container App
• Updated infra/build/deploy scripts and docs
• Removed stripe integration from Functions API (it's in its own service now)
• Wired checkout calls between Functions API and Stripe service
• BREAKING CHANGE: set min Node.js version to >=18 (to use native fetch in Functions)

For another PR(s):

• VNET setup for APIM / API / ACA
• Scenario docs

IMPORTANT: please DO NOT squash this PR and use rebase instead, so we do not lose the Functions -> Container App migration history, and the steps where the stripe/payment/reservation flow is fully working on the Functions (in case it's needed)

[sinedied]

Reminder: IMPORTANT, please DO NOT squash this PR and use rebase instead, so we do not lose the Functions -> Container App migration history, and the steps where the stripe/payment/reservation flow is fully working on the Functions (in case it's needed)