Passkeys improvements (#10318)

Refactors the Passkey implementation to include more checks and a structure that is more aligned with the official specification.
Notable changes:
- _BrowserService_ no longer does the checks by itself. A new class _BrowserPasskeysClient_ constructs the relevant objects, acting as a client. _BrowserService_ only acts as a bridge between the client and _BrowserPasskeys_ (authenticator) and calls the relevant popups for user interaction.
- A new helper class _PasskeyUtils_ includes the actual checks and parses the objects.
- _BrowserPasskeys_ is pretty much intact, but some functions have been moved to PasskeyUtils.
- Fixes Ed25519 encoding in _BrowserCBOR_.
- Adds new error messages.
- User confirmation for Passkey retrieval is also asked even if `discouraged` is used. This goes against the specification, but currently there's no other way to verify the user.
- `cross-platform` is also accepted for compatibility. This could be removed if there's a potential issue with it.
- Extension data is now handled correctly during Authentication.
- Allowed and excluded credentials are now handled correctly.
- `KPEX_PASSKEY_GENERATED_USER_ID` is renamed to `KPEX_PASSKEY_CREDENTIAL_ID`
- Adds a new option "Allow localhost with Passkeys" to Browser Integration -> Advanced tab. By default it's not allowed to access HTTP sites, but `http://localhost` can be allowed for debugging and testing purposes for local servers.
- Add tag `Passkey` to a Passkey entry, or an entry with an imported Passkey.

Fixes #10287.

src/browser/BrowserCbor.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2023 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2024 KeePassXC Team <team@keepassxc.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -35,6 +35,7 @@ enum WebAuthnAlgorithms : int
 // https://www.rfc-editor.org/rfc/rfc9053#section-7.1
 enum WebAuthnCurveKey : int
 {
+    INVALID_CURVE_KEY = 0,
     P256 = 1, // EC2, NIST P-256, also known as secp256r1
     P384 = 2, // EC2, NIST P-384, also known as secp384r1
     P521 = 3, // EC2, NIST P-521, also known as secp521r1
@@ -48,6 +49,7 @@ enum WebAuthnCurveKey : int
 // For RSA: https://www.rfc-editor.org/rfc/rfc8230#section-4
 enum WebAuthnCoseKeyType : int
 {
+    INVALID_COSE_KEY_TYPE = 0,
     OKP = 1, // Octet Keypair
     EC2 = 2, // Elliptic Curve
     RSA = 3 // RSA