chore: remove distributionManagement section (#900)

All java client libraries inherit the distributionManagement section form shared-config. To prevent individual pom files from overriding the shared-config version of distributionManagement, it is being removed.

Author: Neenu1995

google-cloud-bigtable-bom/pom.xml

@@ -48,16 +48,6 @@
         <url>https://github.com/googleapis/java-bigtable</url>
     </scm>
 
-    <distributionManagement>
-        <snapshotRepository>
-            <id>sonatype-nexus-snapshots</id>
-            <url>https://oss.sonatype.org/content/repositories/snapshots</url>
-        </snapshotRepository>
-        <repository>
-            <id>sonatype-nexus-staging</id>
-            <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
-        </repository>
-    </distributionManagement>
 
     <licenses>
         <license>

google-cloud-bigtable-deps-bom/pom.xml

@@ -51,16 +51,6 @@
     <url>https://github.com/googleapis/java-bigtable</url>
   </scm>
 
-  <distributionManagement>
-    <snapshotRepository>
-      <id>sonatype-nexus-snapshots</id>
-      <url>https://oss.sonatype.org/content/repositories/snapshots</url>
-    </snapshotRepository>
-    <repository>
-      <id>sonatype-nexus-staging</id>
-      <url>https://oss.sonatype.org/service/local/staging/deploy/maven2/</url>
-    </repository>
-  </distributionManagement>
 
   <licenses>
     <license>