feat: use stringified tokens for resource attributes instead of strong types (#712)

This change removes all strong-types generated to represent 
CloudFormation resource attributes that return a string  (such 
as `QueueArn`, `DeploymentGroupId`) and replaces them 
with `string` that contains a stringified token (via #518).

This allows working with these attributes as if they were regular
strings, and dramatically simplifies the type-system and unneeded
wrapping when assigning values to such attributes.

The ".ref" property of each resource has been replaced with
a property named according to the actual semantic meaning
of the intrinsic reference (such as `queueArn`), and 
also returns a `string`.

Users can test if a string contains stringified tokens using the function 
`unresolved(o)`, which can be applied to either strings or objects 
(previously was `isToken(o)`).

Fixes #695 (opened #744 to follow up on non-string attributes)

Author: Elad Ben-Israel

Diff for: build.sh

@@ -5,6 +5,11 @@ if [ ! -d node_modules ]; then
     /bin/bash ./install.sh
 fi
 
+fail() {
+  echo "❌  Last command failed. Scroll up to see errors in log."
+  exit 1
+}
+
 /bin/bash ./git-secrets-scan.sh
 
 BUILD_INDICATOR=".BUILD_COMPLETED"
@@ -19,10 +24,10 @@ trap "rm -rf $MERKLE_BUILD_CACHE" EXIT
 
 echo "============================================================================================="
 echo "building..."
-time lerna exec --stream "npm run build"
+time lerna run --no-bail --stream build || fail
 
 echo "============================================================================================="
 echo "testing..."
-lerna run --stream test
+lerna run --no-bail --stream test || fail
 
 touch $BUILD_INDICATOR

Diff for: docs/src/examples.rst

@@ -168,8 +168,8 @@ The following example creates the Aurora database **MyAuroraDatabase**.
        new rds.DatabaseCluster(this, 'MyRdsDb', {
          defaultDatabaseName: 'MyAuroraDatabase',
          masterUser: {
-           username: new cdk.Token('admin'),
-           password: new cdk.Token('123456')
+           username: 'admin',
+           password: '123456'
          },
          engine: rds.DatabaseClusterEngine.Aurora,
          instanceProps: {