Bicep: Add app settings to Functions and Static web app

[DanielLarsenNZ]

@wviriya please populate Key Vault secrets and set App Settings in Functions and Static web app at deployment time. The App settings for each Function are documented here.

Note: Only Cosmos key, connection string and AAD Client Secret need to be stored in Key Vault IMO. The rest of the settings can be ordinary App Settings, as they are not secrets. Application Insights iKey is also not a secret.

• [ ] Create Cosmos Key, Connection string secret in Key Vault
• [ ] Create Graph Client Secret in Key Vault
• [ ] Set Key Vault references in App Settings for all Functions and Static web app
• [ ] Set other settings in App Settings for all Functions and Static web app