CaptiveCrypto for Android native code refactor

[hawkinsji]

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

The native code in the CaptiveCrypto sample app for Android is all in one class and all in one file.
https://github.com/vmware/captive-web-view/blob/main/forAndroid/CaptiveCrypto/src/main/java/com/example/captivecrypto/StoredKey.kt

Describe the solution you'd like

The code should be in several files, perhaps in a package instead of a single class.

Describe alternatives you've considered

No response

Additional context

No response