Unimplemented VaultClientAPIs

[Hoikas]

There are a lot of "eric, implement me" and "eric, port me" assertions in plVaultClientApi. We should really implement these because (in some cases) pfPython uses some of this unimplemented functionality. When implementing them, we should really try not to block. Already entirely too much of the vault API blocks, which is responsible for most of the freezes in the client.

[Hoikas]

This may be addressed by #1486 by simply deleting the unimplemented stuff.

[dpogue]

There are still a few "eric, implement me" assertions, although arguably that's probably an indicator that the function isn't being used

[dgelessus]

Had a quick look over the remaining ones. A few that stand out to me:

• NetCliAuthVaultNodeDelete is impossible to implement with the existing network protocol, because the Cli2Auth_VaultNodeDelete message is undefined
• VaultSetNodeSeen is challenging, as described in KI Incoming read/unread status is broken #1246
• VaultFindOrCreateChildAgeLinkAndWait is unimplemented, unused, and blocking - that can definitely go
• The age chronicle stuff could be useful if implemented - IIRC, some age Python scripts currently do this by hand

The other ones seem to be for things that no longer exist (e. g. age czars) or are implemented elsewhere now (e. g. KI levels and CCR petitions). Those probably aren't worth restoring.