fix(core): reduce CFN template indent size to save bytes (aws#19656)

also: aws/serverless-application-model#2368, cloudtools/troposphere#2028
aws#18694
aws#18886
[CloudFormation templates can currently only be 1MB](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/cloudformation-limits.html)

Simply reducing indentation from 2 to 1 should remove ~1/4 of the template file size for everyone by default while still preserving indentation formatting. Beyond improving the default, those wishing to reduce readability for further reduced file size could opt into using something like [`jq`](https://stedolan.github.io/jq/) on their own for now

----

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### Adding new Unconventional Dependencies:

* [ ] This PR adds new unconventional dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md/#adding-new-unconventional-dependencies)

### New Features

* [ ] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/master/INTEGRATION_TESTS.md)?
	* [ ] Did you use `cdk-integ` to deploy the infrastructure and generate the snapshot (i.e. `cdk-integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/core/lib/stack.ts

@@ -793,7 +793,7 @@ export class Stack extends CoreConstruct implements ITaggable {
         Annotations.of(this).addInfo(`Number of resources: ${numberOfResources} is approaching allowed maximum of ${this.maxResources}`);
       }
     }
-    fs.writeFileSync(outPath, JSON.stringify(template, undefined, 2));
+    fs.writeFileSync(outPath, JSON.stringify(template, undefined, 1));
 
     for (const ctx of this._missingContext) {
       if (lookupRoleArn != null) {

packages/@aws-cdk/pipelines/test/blueprint/stack-deployment.test.ts

@@ -31,7 +31,7 @@ describe('templateUrl', () => {
     const sd = StageDeployment.fromStage(stage);
 
     // THEN
-    expect(sd.stacks[0].templateUrl).toBe('https://cdk-hnb659fds-assets-111-us-east-1.s3.us-east-1.amazonaws.com/93ae4de94f81d0905c37db64b7304f5d65233ca4d9581d3a32215743c9bb92dd.json');
+    expect(sd.stacks[0].templateUrl).toBe('https://cdk-hnb659fds-assets-111-us-east-1.s3.us-east-1.amazonaws.com/21fbb51d7b23f6a6c262b46a9caee79d744a3ac019fd45422d988b96d44b2a22.json');
   });
 
   test('without region', () => {
@@ -43,7 +43,7 @@ describe('templateUrl', () => {
     const sd = StageDeployment.fromStage(stage);
 
     // THEN
-    expect(sd.stacks[0].templateUrl).toBe('https://cdk-hnb659fds-assets-111-.s3.amazonaws.com/$%7BAWS::Region%7D/93ae4de94f81d0905c37db64b7304f5d65233ca4d9581d3a32215743c9bb92dd.json');
+    expect(sd.stacks[0].templateUrl).toBe('https://cdk-hnb659fds-assets-111-.s3.amazonaws.com/$%7BAWS::Region%7D/21fbb51d7b23f6a6c262b46a9caee79d744a3ac019fd45422d988b96d44b2a22.json');
   });
 
 });