Prep for alpha release and versioning update

- Updated `version.json` to `1.0-alpha` for alpha pre-release.
- Added `assemblyVersion` object with `precision` set to `revision`.
- Introduced `cloudBuild` object disabling automatic versioning and build numbers.
- Configured `release` object with `firstUnstableTag` as `alpha`.

Author: chintans

version.json

@@ -1,11 +1,20 @@
 {
     "$schema": "https://raw.githubusercontent.com/dotnet/Nerdbank.GitVersioning/main/src/NerdBank.GitVersioning/version.schema.json",
-    "version": "1.0.0",
+    "version": "1.0-alpha",
+    "assemblyVersion": {
+        "precision": "revision"
+    },
     "publicReleaseRefSpec": [
         "^refs/heads/master$"        
     ],
     "release": {        
         "versionIncrement": "minor",
         "firstUnstableTag": "alpha"
+    },
+    "cloudBuild": {
+        "setVersionVariables": false,
+        "buildNumber": {
+            "enabled": false
+        }
     }
 }