add viewmatcher selector to clients

[KazuCocoa]

Support using="-android viewmatcher", value="<JSON>"

appium/appium-espresso-driver#516

like #12372

Acceptance Criteria:

• Ruby
• Python
• Java
• C#
• WebdriverIO ?
• wd ?

[mykola-mokhnach]

The corresponding changes in espresso driver have been published in version 1.19.0

[o-x-y-g-e-n]

Don't really understand the need to implement this method below
https://github.com/appium/python-client/blob/a2b9440af4dbb07bcb395a7631754844142e34cd/appium/webdriver/extensions/search_context/android.py#L59

onData() or onView() will throw an exception, if it finds multiple elements matching the same criteria.

Let me know what you guys think? @KazuCocoa @mykola-mokhnach

[KazuCocoa]

find elements returns elements as List and does not throw an exception unlike find element. find element should throw an exception if no element found, but find elements returns an empty list. (The error case also espresso driver must return an empty list for find elements call)

[mykola-mokhnach]

Link appium/dotnet-client#408

[mykola-mokhnach]

I believe we have it where needed