fix: both irmaserver and irmaclient now early reject session requests referring nonexisting identifiers

feat: Breaking change: support conjunctions of disjunctions of conjunctions when requesting attributes in any of the three supported session types

Instead of requesting several attributes, one can now request several groups of attributes. Within each such group, attributes belonging to the same credential type always come from the same credential instance. This affects all three session types, as in each of them attributes can be disclosed.

JWTs use URL-encoded base64 (with - _ instead of + /). This fixes parsing bugs
that would occur when issuing attributes containing certain non-alphanumeric
characters like ~.

Fixes #24.
Co-authored-by: Koen van Ingen <koenvaningen@gmail.com>

Co-authored-by: Confiks <confiks@scriptbase.org>

- Sessions now start with a SessionRequest instead of the requestor's JWT
- Move protocol version negotiation to later in the protocol to decouple QR contents from SessionRequest
- Fix legacy in protocol
- Support for multiple keyshare servers in issuance sessions
Co-authored-by: Confiks <confiks@scriptbase.org>

Co-authored-by: Confiks <confiks@scriptbase.org>

Co-authored-by: Confiks <confiks@scriptbase.org>

Co-authored-by: Confiks <confiks@scriptbase.org>

- Extract raw information from session, and only derive for display
- Add protocol version and ABS timestamps in log entries. Include an update function for existing logs
- AttributeValue of AttributeResult is now a TranslatedString
- Removed polymorphic 'response' from log entry; populate either IssueCommitment or Prooflist instead
- Greatly simplified marshalling log entries by not using a separate struct
- Added tests for disclosure logging
Co-authored-by: Sietse Ringers <mail@sietseringers.net>

This also required adding support for calculating the metadata version
based on the protocol version, and sending the current protocol version
to the server as a hint.

The struct name now matches exactly (up to idiomatic spelling differences)
with the name of the folder that it parses and updates.