Use Serverless Azure SQL Database sku plan by default

[paulyuk]

This is a clean issue to track using Serverless SQL SQL per the PR/idea from @ in #9.

In the latest merged Pr (#12) I converted this to use the AVM module. That uses a development grade SKU but it is indeed with provisioned compute:

"sku": {
    "name": "GP_Gen5",
    "tier": "GeneralPurpose",
    "family": "Gen5",
    "capacity": 2
},

But I agree this would be better as a serverless SKU more like this (GP_S_Gen5_1):

    "tier": {
       "value": "GeneralPurpose"
   },
   "skuName": {
       "value": "GP_S_Gen5_1"
   },
   "zoneRedundant": {
       "value": false
   },
   "numberOfReplicas": {
       "value": 0
   },
   "minCapacity": {
       "value": "0.5"
   },

I think this is best to do as a new clean PR synced to latest. If you want to do or collab @danuw please let me know. Otherwise I can quickly make it.

After making the PR change please test it in azd.

[danuw]

Thank you @paulyuk - please go ahead and we can close my PR as a result of this. (Serverless is a good idea too for a start - I assume that enables better overall features without the cost commitment which would be optimal for testing?)