Default repository root

Previously, all of the repository_root declarations in the component
configurations used the common
http://download.pivotal.io.s3.amazonaws.com domain for their
repositories.  Since any user wanting to move the repositories to a
different location (e.g. replication behind a firewall) would have to
change many files, this change abstracts the repository root
declaration.  It does this by introducing a {default.repository.root}
substitution variable for repository_roots.  This placeholder is
substituted with a value configured in config/repository.yml.  The use
of this placeholder is not required.

[#57585912]

Author: nebhale

.idea/codeStyleSettings.xml

@@ -41,7 +41,7 @@ To learn how to configure various properties of the buildpack, follow the "Confi
 * Utilities
 	* [Caches](docs/util-caches.md) ([Configuration](docs/util-caches.md#configuration))
 	* [Logging](docs/logging.md) ([Configuration](docs/logging.md#configuration))
-	* [Repositories](docs/util-repositories.md)
+	* [Repositories](docs/util-repositories.md) ([Configuration](docs/util-repositories.md#configuration))
 	* [Other Utiltities](docs/util-other.md)
 	* [Repository Builder](docs/util-repository-builder.md)
 	* [Test Applications](docs/util-test-applications.md)

.idea/dictionaries/bhale.xml

@@ -16,5 +16,5 @@
 # Configuration for the New Relic framework
 ---
 version: 3.7.+
-repository_root: "http://download.pivotal.io.s3.amazonaws.com/app-dynamics"
+repository_root: "{default.repository.root}/app-dynamics"
 tier_name: Cloud Foundry

.idea/misc.xml

@@ -16,4 +16,4 @@
 # Configuration for the Groovy container
 ---
 version: 2.1.+
-repository_root: "http://download.pivotal.io.s3.amazonaws.com/groovy"
+repository_root: "{default.repository.root}/groovy"

.idea/runConfigurations/All_Tests.xml

@@ -16,4 +16,4 @@
 # Configuration for the MariaDB JDBC framework
 ---
 version: 1.1.+
-repository_root: "http://download.pivotal.io.s3.amazonaws.com/mariadb-jdbc"
+repository_root: "{default.repository.root}/mariadb-jdbc"

.idea/runConfigurations/Without_Integration_Tests.xml

@@ -16,4 +16,4 @@
 # Configuration for the New Relic framework
 ---
 version: 3.1.+
-repository_root: "http://download.pivotal.io.s3.amazonaws.com/new-relic"
+repository_root: "{default.repository.root}/new-relic"