gocognit split: token/services misc (tokens, auditor, certifier, interop/htlc, driver) #2387

Part of #2377.

Re-apply the gocognit complexity-reduction extraction for the remaining token/ and token/services/ packages not covered by the other sub-issues, removing the temporary //nolint:gocognit // TODO(#2377) markers #2327 leaves on them.

Files in scope:

• token/request.go
• token/vault.go
• token/driver/request.go
• token/services/tokens/tokens.go
• token/services/auditor/config.go
• token/services/certifier/interactive/driver.go
• token/services/certifier/views/register.go
• token/services/interop/htlc/transaction.go