techdocs: Replace nodegit with isomorphic-git

TechDocs needs 4 functions from the git library
1. To clone 2. To get the commit timestamp for HEAD 3. To fetch 4. To merge two branches

Created necessary commands in the new SCM client and reordered them alphabetically for convenience

plugins/scaffolder-backend/src/scaffolder/stages/prepare/azure.ts

@@ -57,7 +57,7 @@ export class AzurePreparer implements PreparerBase {
       template.spec.path ?? '.',
     );
 
-    // Username can anything but the empty string according to:
+    // Username can be anything but the empty string according to:
     // https://docs.microsoft.com/en-us/azure/devops/organizations/accounts/use-personal-access-tokens-to-authenticate?view=azure-devops&tabs=preview-page#use-a-pat
     const git = this.privateToken
       ? Git.fromAuth({