Use application.properties for configuration

Updated to quarkusio/quarkus#1110 change

_guides/application-configuration-guide.adoc

@@ -93,8 +93,8 @@ public String hello() {
 
 == Create the configuration
 
-By default, Quarkus reads `META-INF/microprofile-config.properties`.
-Edit the `src/main/resources/META-INF/microprofile-config.properties` with the following content:
+By default, Quarkus reads `application.properties`.
+Edit the `src/main/resources/application.properties` with the following content:
 
 [source]
 ----
@@ -107,7 +107,7 @@ Once set, check the application with:
 
 [source]
 ----
-$ curl  http://localhost:8080/greeting
+$ curl http://localhost:8080/greeting
 hello quarkus!
 ----
 
@@ -154,4 +154,4 @@ Changing the configuration file is immediately reflected.
 You can add the `greeting.suffix`, remove the other properties, change the values, etc.
 
 As usual, the application can be packaged using `mvn clean package` and executed using the `-runner.jar` file.
-You can also generate the native executable with `mvn clean package -Pnative`.
+You can also generate the native executable with `mvn clean package -Pnative`.