Add dropbear-ssh 0.1.0 (kindlehf)

[akshaylahudkar]

Adds dropbear-ssh — on-demand SSH/SFTP over WiFi for jailbroken Kindles, repackaging notmarek/kindle-usbnetlite's dropbear binaries as a KPM hook package (upstream's own OTA/mrpackages installer no longer works on modern jailbreaks — it depends on a no-longer-bundled MRInstaller extension).

• Random per-install password, printed in the KPM log and readable afterward at /mnt/us/usbnetlite/etc/ssh_password; can be preset before install via a dropbear_password.txt staging file.
• Listens on port 2022 (KOReader's own bundled dropbear already uses 2222).
• Only binds the Kindle's WiFi interface, not reachable from the internet unless separately port-forwarded.

Tested end-to-end (install → launch → real SSH session → survives upgrade/downgrade) on a Kindle PaperWhite 4, kernel 4.1.x — this PR only submits that kindlehf artifact. There's a second binary build for the broader kindlehf/older device range that's currently execute-verified only (a real connection attempt crashed mid-SSH-handshake on the one non-PW4 device available), so I'm holding that back for a follow-up PR once it's actually connection-tested on real hardware, per the repo's Creating a Repository guidance to submit here rather than host a separate repo.

Source (install.sh/launch.sh/uninstall.sh, unmodified binaries via kindletool extract) is at https://github.com/akshaylahudkar/dropbear-ssh — happy to make any changes requested.