Added DB helper for screenshotDb.
Added DB helper for screenshotDb.

rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android,rfcx/rfcx-guardian-android