Merge /etc/map documentation with sling site page
As the rest of the /etc/map documentation was there already, the interpolation docs have been moved there with https://github.com/apache/sling-site/commit/eb5cf32c986f3ea60158e0808cf92634cbedb35d
diff --git a/README.md b/README.md
index c84dca7..b1aa692 100644
--- a/README.md
+++ b/README.md
@@ -6,74 +6,7 @@
This module is part of the [Apache Sling](https://sling.apache.org) project.
-This bundle provides the Resource Resolver and Resource Resolver Factory
+This bundle provides the Resource Resolver and Resource Resolver Factory.
-## ETC Map String Interpolation
-
-Setting up ETC Mappings (/etc/map) for different instances like dev, stage,
-qa and production was time consuming and error prone due to copy-n-paste
-errors.
-As a new feature Sling now supports String Interpolation in the /etc/map.
-With this it is possible to add placeholders to **sling:match** entries
-to make it possible to have them work for different environments.
-The values are either provides by System, Bundle Context or String
-Interpolation Configuration values.
-The placeholders have this format: **$['type':'name';default='default value']**.
-The type is can be:
-* **env**: take from the System Properties
-* **prop**: taken from the Bundle Context Properties
-* otherwise: taken from the String Interpolation Configuration
-
-With it it is possible to create a single set of etc-mapping and then adjust
-the actual values of an instance by an OSGi configuration.
-**Note**: the placeholder **must be placed** into a **sling:match** entry
-and cannot be the JCR Node Name as some of the characters are not allowed.
-
-### Setup
-
-The Substitution Configuration can be found in the OSGi Configuration
-as **Apache Sling String Interpolation Provider**. The property **Placeholder
-Values** takes a list of **key=value** entries where each of them map a
-variable with its actual value.
-In our little introduction we add an entry of
-**phv.default.host.name=localhost**. Save the configuration for now.
-Before going on make sure that you know Mapping Location configuration
-in the OSGi configuration of **Apache Sling Resource Resolver Factory**.
-Now to to **composum** and go to that node. If it does not exist then create
-one. The mapping should look like this:
-* etc
- * map
- * http
- * my-mapping
- * sling:match=$\[phv.fq.host.name\].8080
-
-Opening the page **http://localhost:8080/starter/index.html** should
-work just fine.
-This is a mapping from System Properties with a default:
-* etc
- * map
- * http
- * my-mapping
- * sling:match=$\[env:phv.fq.host.name;default=localhost\].8080
-
-### Testing
-
-Now got back to the String Interpolation configuration and change the value
-to **qa.author.acme.com** and save it.
-
-For local testing open your **hosts** file (/etc/hosts on Unix) and add a
-line like this:
-```
-127.0.0.1 qa.author.acme.com
-```
-save it and test with `ping qa.author.acme.com` to make sure the name
-resolves.
-Now you should be able to open the same page with:
-**http://qa.author.acme.com/starter/index.html**.
-
-Now do the same with **phv.fq.host.name=staging.author.acme.com**.
-
-The String Interpolation works with any part of the etc-map tree.
-
-
-
+The `/etc/map` mapping configurations are documented on the Sling website's
+[Mappings for Resource Resolution](https://sling.apache.org/documentation/the-sling-engine/mappings-for-resource-resolution.html) page.
