refactor: Deprecate Appium ByAll

Appium `io.appium.java_client.pagefactory.bys.builder.ByAll` was implemented as an extension of Selenium `org.openqa.selenium.support.pagefactory.ByAll` and introduced a performance improvement: "By All was re-implemented, now it returns the first founded element for single search." (appium#686 on 3 Aug 2017).
However Selenium team introduced the same performance fix "SeleniumHQ/selenium@18028ac ByAll.findElement should not not use remaining locators if an element is already found" on 7 Sep 2017.
So there is no reason to keep Appium `ByAll`, this commit deprecates it.

Author: valfirst

src/main/java/io/appium/java_client/pagefactory/DefaultElementByBuilder.java

@@ -23,7 +23,6 @@
 import io.appium.java_client.pagefactory.bys.ContentMappedBy;
 import io.appium.java_client.pagefactory.bys.ContentType;
 import io.appium.java_client.pagefactory.bys.builder.AppiumByBuilder;
-import io.appium.java_client.pagefactory.bys.builder.ByAll;
 import io.appium.java_client.pagefactory.bys.builder.ByChained;
 import io.appium.java_client.pagefactory.bys.builder.HowToUseSelectors;
 import org.openqa.selenium.By;
@@ -32,6 +31,7 @@
 import org.openqa.selenium.support.FindAll;
 import org.openqa.selenium.support.FindBy;
 import org.openqa.selenium.support.FindBys;
+import org.openqa.selenium.support.pagefactory.ByAll;
 
 import java.lang.annotation.Annotation;
 import java.lang.reflect.AnnotatedElement;

src/main/java/io/appium/java_client/pagefactory/bys/builder/AppiumByBuilder.java

@@ -24,6 +24,7 @@
 
 import org.openqa.selenium.By;
 import org.openqa.selenium.support.pagefactory.AbstractAnnotations;
+import org.openqa.selenium.support.pagefactory.ByAll;
 
 import javax.annotation.Nullable;
 import java.lang.annotation.Annotation;

src/main/java/io/appium/java_client/pagefactory/bys/builder/ByAll.java

@@ -13,7 +13,20 @@
 import java.util.Optional;
 import java.util.function.Function;
 
-
+/**
+ * Mechanism used to locate elements within a document using a series of  lookups. This class will
+ * find all DOM elements that matches any of the locators in sequence, e.g.
+ *
+ * <pre>
+ * driver.findElements(new ByAll(by1, by2))
+ * </pre>
+ *
+ * will find all elements that match <var>by1</var> and then all elements that match <var>by2</var>.
+ * This means that the list of elements returned may not be in document order.
+ * 
+ * @deprecated Use {@link org.openqa.selenium.support.pagefactory.ByAll}
+ */
+@Deprecated
 public class ByAll extends org.openqa.selenium.support.pagefactory.ByAll {
 
     private final List<By> bys;