Add PulsarReader section to docs (#336)

- Use template var for pulsar docs url

spring-pulsar-docs/src/main/asciidoc/authentication.adoc

@@ -1,3 +1,6 @@
+
+include::attributes.adoc[]
+
 To connect to a Pulsar cluster that requires authentication, you need to set the `authPluginClassName` and any parameters required by the authentication plugin. You can set the parameters as a single JSON-encoded string or as map of parameter names to parameter values. The following listings show both approaches:
 
 [source,yaml,indent=0,role="primary"]
@@ -131,5 +134,4 @@ spring:
 ----
 ====
 
-
-NOTE: You can find more information on each of the schemes and their required properties in the official link:https://pulsar.apache.org/docs/security-overview#authentication-providers[Pulsar security] documentation.
+NOTE: You can find more information on each of the schemes and their required properties in the official {apache-pulsar-docs}/security-overview#authentication-providers[Pulsar security] documentation.

spring-pulsar-docs/src/main/asciidoc/index.adoc

@@ -33,7 +33,7 @@ In addition to this reference documentation, we recommend a number of other reso
 
 - {github}[Spring for Apache Pulsar GitHub Repository]
 - https://pulsar.apache.org/[Apache Pulsar Project Home Page]
-- https://pulsar.apache.org/docs/client-libraries-java/[Apache Pulsar Java Client]
+- {apache-pulsar-docs}/client-libraries-java/[Apache Pulsar Java Client]
 - https://github.com/apache/pulsar[Apache Pulsar GitHub Repository]
 - https://github.com/apache/pulsar-client-reactive[Apache Pulsar Reactive Client GitHub Repository]
 

spring-pulsar-docs/src/main/asciidoc/pulsar-function.adoc

@@ -72,7 +72,7 @@ The action that occurs during the create/update operation is dependent on path "
 Apache Pulsar provides many source and sink connectors out-of-the-box, aka built-in connectors. To use a built-in connector simply set the `archive` to `builtin://<connector-type>` (eg `builtin://rabbit`).
 
 == Custom functions
-The details on how to develop and package custom functions can be found in the https://pulsar.apache.org/docs/2.10.x/functions-develop[Pulsar docs].
+The details on how to develop and package custom functions can be found in the {apache-pulsar-docs}/functions-develop[Pulsar docs].
 However, at a high-level, the requirements are as follows:
 
 * Code uses Java8

spring-pulsar-docs/src/main/asciidoc/pulsar.adoc

@@ -1129,6 +1129,13 @@ void someMethod() {
 
 TIP: The id parameter passed to `getListenerContainer` is the container id - which will be the value of the `@PulsarListener` id attribute when pausing/resuming a `@PulsarListener`.
 
+[[imperative-pulsar-reader]]
+=== Pulsar Reader Support
+The framework provides support for using {apache-pulsar-docs}/concepts-clients/#reader-interface[Pulsar Reader] via the `PulsarReaderFactory`.
+
+Spring Boot provides this reader factory which can be configured with any of the <<application-properties.adoc#appendix.application-properties.pulsar-reader,`spring.pulsar.reader`>> prefixed application properties.
+
+
 
 == Publishing and Consuming Partitioned Topics
 

spring-pulsar-docs/src/main/asciidoc/reactive-pulsar.adoc

@@ -492,6 +492,6 @@ The easy way to solve this is to provide a DLQ topic name always.
 
 [[reactive-pulsar-reader]]
 === Pulsar Reader Support
-The framework provides support for using https://pulsar.apache.org/docs/2.10.x/concepts-clients/#reader-interface[Pulsar Reader] in a Reactive fashion via the `ReactivePulsarReaderFactory`.
+The framework provides support for using {apache-pulsar-docs}/concepts-clients/#reader-interface[Pulsar Reader] in a Reactive fashion via the `ReactivePulsarReaderFactory`.
 
 Spring Boot provides this reader factory which can be configured with any of the <<application-properties.adoc#appendix.application-properties.pulsar-reactive-reader,`spring.pulsar.reactive.reader`>> prefixed application properties.