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.