Drop Maven support

Maintaining two build systems is just a huge waste of time.

Change-Id: Ie2ed1cc048bc327978926a3376a6570432322bb8

pom.xml

diff --git a/pom.xml b/pom.xml
deleted file mode 100644
index c53a415..0000000
--- a/pom.xml
+++ /dev/null
@@ -1,65 +0,0 @@
-<?xml version="1.0"?>
-<project
-  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"
-  xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
-  <modelVersion>4.0.0</modelVersion>
-  <artifactId>gravatar-avatar-provider</artifactId>
-  <groupId>com.googlesource.gerrit.plugins.avatar_providers</groupId>
-  <version>2.11</version>
-  <packaging>jar</packaging>
-  <properties>
-    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <Gerrit-ApiType>PLUGIN</Gerrit-ApiType>
-    <Gerrit-ApiVersion>${project.version}</Gerrit-ApiVersion>
-  </properties>
-
-  <build>
-    <plugins>
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-jar-plugin</artifactId>
-        <version>2.4</version>
-        <configuration>
-          <archive>
-            <manifestEntries>
-              <Implementation-Title>Gerrit Code Review - gravatar image provider</Implementation-Title>
-              <Implementation-Version>${project.version}</Implementation-Version>
-              <Implementation-Vendor>Gerrit Code Review</Implementation-Vendor>
-              <Implementation-Vendor-URL>http://code.google.com/p/gerrit/</Implementation-Vendor-URL>
-              <Gerrit-ApiType>${Gerrit-ApiType}</Gerrit-ApiType>
-              <Gerrit-ApiVersion>${Gerrit-ApiVersion}</Gerrit-ApiVersion>
-              <Gerrit-PluginName>gravatar-avatar-provider</Gerrit-PluginName>
-            </manifestEntries>
-          </archive>
-        </configuration>
-      </plugin>
-
-      <plugin>
-        <groupId>org.apache.maven.plugins</groupId>
-        <artifactId>maven-compiler-plugin</artifactId>
-        <version>2.3.2</version>
-        <configuration>
-          <source>1.6</source>
-          <target>1.6</target>
-          <encoding>UTF-8</encoding>
-        </configuration>
-      </plugin>
-    </plugins>
-  </build>
-
-  <dependencies>
-    <dependency>
-      <groupId>com.google.gerrit</groupId>
-      <artifactId>gerrit-plugin-api</artifactId>
-      <version>${Gerrit-ApiVersion}</version>
-      <scope>provided</scope>
-    </dependency>
-  </dependencies>
-
-  <repositories>
-    <repository>
-      <id>gerrit-api-repository</id>
-      <url>https://gerrit-api.commondatastorage.googleapis.com/release/</url>
-    </repository>
-  </repositories>
-</project>