First sketch of security considerations

Closes #7

See merge request open/cryptops!2

start documentation in sphinx

Closes #1

See merge request !1

Run notification hook on startup

Closes #26

See merge request !22

Free memory after use

Closes #21

See merge request !21

# Conflicts:
#   src/api/encryption_init_post.c

Make device paths runtime configurable

Closes #24

See merge request !19

Add endpoint for selfdestruct

Closes #23

See merge request !18

On selfdestruct, first destroy all active keyslots through the
cryptsetup library, before zeroing the luks header.

Also take a factor two safety margin when zeroing the luks header,
and halt the machine (instead of rebooting) after selfdestruct.

Add endpoint for deleting encryption key

Closes #6

See merge request !15

# Conflicts:
#   src/cryptops-api.c

When deleting an encryption key, check if there is at least one other
active keyslot, and do not delete if there isn't.

Resolve "Makefile does not track c file changes"

Closes #22

See merge request !16

Add endpoint for adding encryption key

Closes #5

See merge request !14