Remove samples for v3 beta SDK

[antonsurya]

Is your feature request related to a problem? Please describe.

The repo contains sample codes for v3 beta SDK that developers should not use anymore. The beta SDK was deprecated in August 2021: https://developers.google.com/maps/documentation/android-sdk/release-notes#august_18_2021

Describe the solution you'd like

Remove samples for v3 beta SDK.

Describe alternatives you've considered

Do nothing. However, it may confuse new SDK users, e.g. #958

[kikoso]

Hi @antonsurya ,

The v3 folders are still being used for some automation mechanisms in place to generate documentation and others. They will be removed at some point in the future.

[antonsurya]

Thank you for the explanation.