SLING-8012 - Extract an HTL runtime bundle from the existing HTL modules

* improved documentation about dependencies needed when compiling HTL scripts
in a project
diff --git a/pom.xml b/pom.xml
index 934f180..6091b49 100644
--- a/pom.xml
+++ b/pom.xml
@@ -50,10 +50,13 @@
     <properties>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <site.jira.version.id>12336741,12338350,12338646,12338974,12341271,12342047,12342267,12342272,12343462,
-            12343846,12344079</site.jira.version.id>
+            12343846,12344079,12344332</site.jira.version.id>
         <maven.version>3.3.9</maven.version>
         <maven.site.path>${project.artifactId}-archives/${project.artifactId}-LATEST</maven.site.path>
         <jacoco.version>0.8.1</jacoco.version>
+        <sightly.runtime.version>1.0.0-1.4.0-SNAPSHOT</sightly.runtime.version>
+        <sightly.compiler.version>1.1.0-1.4.0-SNAPSHOT</sightly.compiler.version>
+        <sightly.compiler.java.version>1.1.0-1.4.0-SNAPSHOT</sightly.compiler.java.version>
         <argLine />
     </properties>
 
@@ -93,17 +96,17 @@
         <dependency>
             <groupId>org.apache.sling</groupId>
             <artifactId>org.apache.sling.scripting.sightly.runtime</artifactId>
-            <version>1.0.0-1.4.0-SNAPSHOT</version>
+            <version>${sightly.runtime.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.sling</groupId>
             <artifactId>org.apache.sling.scripting.sightly.compiler</artifactId>
-            <version>1.1.0-1.4.0-SNAPSHOT</version>
+            <version>${sightly.compiler.version}</version>
         </dependency>
         <dependency>
             <groupId>org.apache.sling</groupId>
             <artifactId>org.apache.sling.scripting.sightly.compiler.java</artifactId>
-            <version>1.1.0-1.4.0-SNAPSHOT</version>
+            <version>${sightly.compiler.java.version}</version>
         </dependency>
         <dependency>
             <groupId>commons-io</groupId>
diff --git a/src/site/markdown/usage.md.vm b/src/site/markdown/usage.md.vm
index 9429805..53fe3bf 100644
--- a/src/site/markdown/usage.md.vm
+++ b/src/site/markdown/usage.md.vm
@@ -92,3 +92,35 @@
     ...
 </project>
 ```
+
+Additionally, the following dependencies are required as part of your project's dependencies list:
+
+```
+<!-- HTL dependencies needed for the HTL Maven Plugin source code generation -->
+<dependency>
+    <groupId>org.apache.sling</groupId>
+    <artifactId>org.apache.sling.scripting.sightly.compiler</artifactId>
+    <!-- version 1.0.14 or higher -->
+    <version>1.0.14</version>
+    <scope>provided</scope>
+</dependency>
+<dependency>
+    <groupId>org.apache.sling</groupId>
+    <artifactId>org.apache.sling.scripting.sightly.compiler.java</artifactId>
+    <!-- version 1.0.16 or higher -->
+    <version>1.0.16</version>
+    <scope>provided</scope>
+</dependency>
+```
+
+Starting with version 1.2.2 of the `htl-maven-plugin`, only the following dependency is needed as part of your project's dependency list:
+
+```
+<!-- HTL dependencies needed for the HTL Maven Plugin source code generation -->
+<dependency>
+    <groupId>org.apache.sling</groupId>
+    <artifactId>org.apache.sling.scripting.sightly.runtime</artifactId>
+    <version>$context.get("sightly.runtime.version")</version>
+    <scope>provided</scope>
+</dependency>
+```