wip: track access token usage

[msmithstubbs]

This PR implements API access token usage based on the usage model in #3592

• Access token usage is tracked in LogflareWeb.Plugs.VerifyApiAccess once the access token is identified as valid
• Usage is initially recorded in a local node cache
• Every 5 minutes AccessTokenUsageSyncWorker polls each node and fetches access token timestamps and persists them in the table oauth_access_token_usages. A separate table is used so updating the last_used_at field won't trigger a cache eviction for the access token
• Last used timestamp is displayed in the AccessTokensLive UI table. Access tokens without a last used record show Unknown: never would be misleading for access tokens accessed before tracking was implemented.

Small UI refactor for AccessTokensLive:

• Extract table HTML into CoreComponents.table/1
• Last used and created timestamps are displayed in the table in the user's local timezone
• Action buttons are aligned vertically

Closes O11Y-2479