I wrote a function handleOutboxNote that's supposed to do the whole outbox POST
handler process. There's an outbox item table in the DB now, I adapted things
in various source files. Ticket comment federation work is still in progress.
* Adapt DB related code to return the InstanceId and RemoteSharerId
* Previously, when fetching a known shared key, we were running a DB
check/update for the shared usage record. I noticed - and hopefully I
correctly noticed - that this check already runs when we discover the keyId
points to a shared key we already know. So, after successful sig
verification, there's no need to run the check again. So I removed it.
Before, things worked like this:
* Only signatures of Ed25519 keys could be verified
* Key encoding placed the plain binary Ed25519 key in the PEM, instead of the
key's ASN1 encoding
With this patch it now works like this:
* Ed25519 signatures are supported as before
* RSA keys are now supported too, assuming RSA-SHA256 signatures
* Both Ed25519 and RSA keys are encoded and decoded using actual PEM with ASN1
