fixes #3220

apparently using conscrypt on Android below version 7? throws an exception when using 16 byte IVs.
so we now use BC when ever possible (excluding api 28)

we don’t know why Conscrypt behaves differently on various android versions

fixes #3221

...so no useless icon is shown on the status bar on Android 7 and older (as it was up to 2.2.9)

Merge branch 'video-selector' of https://github.com/licaon-kter/Conversations into licaon-kter-video-selector

fixes #3202, closes #3193, closes #3214

case ONLY_INTERNAL_STORAGE = true

clients like Dino can’t handle 12 byte IVs

The general security check is recommend so a third party can not ask us to send an internal file. But we don’t need to do this for files we attach ourself from within Conversations

The shortcut didn’t take care of message edits and some other things

Conscrypt on some plattforms doesn’t like when we close the CipherInputStream. Therefor we refactor the api to give us access to the inner stream so we can close that independently.