enterprise audit trail for certain actions

[tomholub]

#3015 is related. In production enterprise deployment, this event logging functionality only gets activated when there is FES configured to send these logs to. This means that AccountServer will have a method like

AccountServer.logEvent(acctEmail: string, tags: EventTag[], description: string, details?: string)

or maybe even:

AccountServer.logEvent(accessToken: string, tags: EventTag[], description: string, details?: string)

Then tags may be:

export type EventTag = 'auth' | 'setup' | 'keypair' | 'pubkey';

actions like:

• authentication with google
• authentication with backend, org rules
• setup requests sent to ekm, responses
• finish setup
• new key generated
• pubkey loaded into keyring (manual or automatic)
• pubkey in keyring updated (manual or automatic)
• extension uninstall
• remaining mentioned situations as per https://github.com/FlowCrypt/enterprise-server/issues/4

These would be sent to an endpoint as per #2689 for logging. Related issue on FES https://github.com/FlowCrypt/enterprise-server/issues/26

Further, for later: each request should have user action event id, so that if there is an event like initial setup, you could tie all the relevant requests together across the client, backend and EKM.