Instead of simply encrypting the private key with AES-256 when storing it to
the 'encrypted_private_key' file, wrap it using the AES-key-wrap algorithm
described in RFC 3394 "Advanced Encryption Standard (AES) Key Wrap Algorithm".
This is more secure and enables us to directly check whether the passphrase
entered by the user was correct or not.
Ref #4032
Instead of using the user passphrase directly, use its SHA256 hash calculated
using libcrypto. The passphrase hash is still stored in the key file to be
used as base for the very primitive way of generating the private key.
Ref #4032
The CBE repository contained a lot of Genode-specific code despite the fact
that the CBE core logic is not bound to Genode in any way. Therefore the
Genode-specific CBE code is moved to the 'gems' repository to form part of
Genode mainline. The remaining CBE code becomes a port in Genode instead of
being invoked as sub-repository.
The commit combines the following work steps:
* add all files removed from CBE repository
* add CBE port files
* make all CBE libs and targets build again
* make all CBE run scripts succeed again
* make all CBE recipes build again
* make CBE autopilot succeed again
* let CBE autopilot use 'libsparcrypto' contrib dir and Genode build dir
instead of '.ci' dir in CBE contrib dir (remove '.ci' dir from CBE repo)
* let CBE autopilot always check for all ports
* make CBE autopilot directly executable
* fix license headers in all Genode CBE files
* remove unused VFS replay component
* remove unused CBE test
* remove unused external crypto
* remove unused files in run dir
* remove unused external trust anchor
* add cbe_tester test to autopilot list
* get rid of directories 'include/cbe_*' and 'include/utils'
Fixes#3937
