customize user agent to match that of the app and version

feel free to use this code from my project at will. also uses okhttp. it's useful to understand device information as well as doing possible work-arounds.

https://github.com/amahi/android/blob/87121f31fb39a9c54a9beda7b406830d02d1b93f/src/main/java/org/amahi/anywhere/util/Identifier.java

Read the linked Amahi Identifier.java example first, then locate where this Android project configures its OkHttp requests. Clarify the intended app and version format and which device information is required; done means requests use the agreed user agent and the documented compatibility workarounds are covered.

Written by the indexing model from the issue text.