Audit server metrics for eco_anon_id mgmt

[data-sync-user]

We should verify that all the correct metrics are logged for the new AET feature. This includes events for creation, deletion, updated etc.

┆Issue is synchronized with this Jira Task ┆Issue Number: FXA-1909

[jaredhirsch]

I did find one obscure spot we missed, and updated the auth-server docs with another missed update:

New endpoints specific to AET

Profile server

GET /v1/ecosystem_anon_id

• added a logger call. ✅

POST /v1/ecosystem_anon_id

• we log using mozlog under the routes.ecosystem_anon_id.post route header

Auth server

PUT /account/ecosystemAnonId

• we log using mozlog via a log.begin('account.updateEcosystemAnonId') call

Auth-db server

PUT /account/:uid/ecosystemAnonId

• logging is baked in for all db-server routes, including this new one

The eco_anon_id otherwise flows from auth-db to auth via the existing account-related GET calls, and from auth to profile via the existing GET _core_profile call.