Add endpoint for changing encryption passwords

Closes #5

See merge request !8

Rename encryption/add to encryption/init

Closes #17

See merge request !7

Listen only to localhost

Closes #15

See merge request !6

# Conflicts:
#   src/includes/common-includes.h
#   src/includes/settings.h

Repartition and populate config partition on init

Closes #12

See merge request !5

# Conflicts:
#   src/includes/settings.h

Add endpoint for listing ssh keys

Closes #7

See merge request !4

Extend the `encryption/add` command to repartition the encrypted container,
copy the authorized_keys file to the configuration partition, generate a new
ssh host key for the dropbear running in the initrd, and reboot after it's
done.

Add encryption endpoint

See merge request !3

Resolve "Make a decryption API endpoint"

See merge request !1