Extension Libs from Maven Repository

Hello,

I am doing an extension that needs classes from appcompat-v7 and play-services, so I declared them in ext.yml as:
maven_deps: ['com.google.android.gms:play-services-....', 'com.android.support:appcompat-v7:27.1.1']

The problem is that from Android Studio 3.0.2 this libraries are no more in sdk extras m2repository directory:

So I have to add the google and jcenter maven repos in pom.erb template:

<repository>
<id>1000</id>
<name>repo-google</name>
<url>https://maven.google.com</url>
</repository>
<repository>
<id>1010</id>
<name>jcenter</name>
<url>https://jcenter.bintray.com/</url>
</repository>
</repositories>

Is there a way to include this repos without touching pom.erb?
Why this repos are not in pom.erb?

How to include libraries that require jar files?

Another problem is the libraries download from repo every time I build.