MainActivity: connection test: print host key
does not store and verify it in SAF yet, but it is a step forward
MainActivity: run connection test on another thread
MainActivity: add a button for testing connection
SFTPDocumentsProvider: set dummy flag
we do not support any of the flags yet, but this should prevent
DocumentsUI with docinfo from crashing
SFTPDocumentsProvider: unify stat filling
SFTPDocumentsProvider: make title url-ish
SFTPDocumentsProvider: append mount path to title
SFTPDocumentsProvider: do not add port to title if canonical
SFTPDocumentsProvider: add summary
SFTPDocumentsProvider: correct connection resetting
SFTPDocumentsProvider: proper error handling
SFTPDocumentsProvider: refactor toasting
build: bump sshlib to 2.2.20
seekable reader, bump min sdk level to 26
build: modernize toolchain
README: we support custom path now
don't reuse SFTPv3Client, it's not costy and this enables concurrency
ReadTask: always try to close the file