Added VNet Peering snippet

[StefanIvemo]

Added a snippet for Virtual Network Peering.

Contributing a snippet

• I have only a single resource in my snippet
• I have checked that there is not an equivalent snippet already submitted
• I have used camelCasing unless I have a justification to use another casing style
• I have placeholders values that correspond to their property names (e.g. dnsPrefix: 'dnsPrefix'), unless it's a property that MUST be changed or parameterized in order to deploy. In that case, I use 'REQUIRED' e.g. keyData
• I have my symbolic name as the first tab stop ($1) in the snippet. e.g. res-aks-cluster.bicep
• I have a resource name property equal to "name"