Security Vulnerability: Sensitive Data Stored on External Storage

[michael2to3]

i2pd for Android has a security vulnerability: all configuration data, including tunnel keys, is stored on external storage (e.g., SD card). This exposes the data to potential access and modification by any application granted access to the SD card, risking key leakage, unauthorized configuration changes, and security breaches.

Suggested Fix:

Store sensitive data, such as tunnel keys and configurations, in internal storage to prevent unauthorized access and ensure data security.

[r4sas]

Feel free to create PR to make such change, but in that case you will cut users from ability to modify configuration files.
If anyone would write whole GUI configuration stuff - we will accept it.