Update dependency repos (#760)

Add mavenCentral to replace jcenter, which is now deprecated.

Remove unused sonatype.org repo. Also remove missing servo.org repo.

Bundle openwnn-1.3.7.aar, our one dependency that is only available in JCenter.
Remove references to "openwnn"

Remove unused flatDir

app/build.gradle

@@ -507,15 +507,8 @@ configurations {
     x86Implementation
 }
 
-repositories {
-    flatDir {
-        dirs 'aars'
-    }
-}
-
 dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    implementation deps.openwnn
 
     // Common
     implementation deps.lifecycle.runtime
@@ -648,6 +641,9 @@ dependencies {
     if (isWebKitAvailable()) {
         webkitImplementation fileTree(dir: gradle."userProperties.webkit_aar", include: ['*.aar'])
     }
+
+    // openwnn (bundled because it is not published outside of JCenter, which is deprecated)
+    implementation fileTree(dir: "${project.rootDir}/libs/openwnn/", include: ['*.aar'])
 }
 
 if (findProject(':servo')) {

versions.gradle

@@ -33,7 +33,6 @@ versions.android_components = "75.0.22"
 // that we depend on directly for its rustlog package, and it's important
 // that it be kept insync with the version used by android-components above.
 versions.mozilla_appservices = "74.0.1"
-versions.openwnn = "1.3.7"
 versions.room = "2.2.0"
 versions.lifecycle = "2.3.1"
 versions.cardview = "1.0.0"
@@ -99,9 +98,6 @@ def app_services = [:]
 app_services.rustlog = "org.mozilla.appservices:rustlog:${versions.mozilla_appservices}"
 deps.app_services = app_services
 
-
-deps.openwnn = "jp.co.omronsoft.openwnn:openwnn:$versions.openwnn"
-
 def support = [:]
 support.annotations = "androidx.annotation:annotation:1.1.0"
 support.app_compat = "androidx.appcompat:appcompat:1.4.2"
@@ -198,10 +194,8 @@ ext.deps = deps
 
 def addRepos(RepositoryHandler handler) {
     handler.google()
-    handler.jcenter()
-    handler.maven { url 'https://oss.sonatype.org/content/repositories/snapshots' }
+    handler.mavenCentral()
     handler.maven { url 'https://maven.mozilla.org/maven2' }
-    handler.maven { url 'https://download.servo.org/nightly/maven' }
     handler.maven { url 'https://developer.huawei.com/repo/' }
 }
 ext.addRepos = this.&addRepos