List when each token was last accesssed

__Proposal:__
As a developer using InfluxdB
I want to see when a token was last used
So that I can turn off, or delete, unused tokens for better security hygiene.

__Current behavior:__
Here's a screenshot of the tokens in my InfluxDB instance. It's been a while so I've set up the instance, so I have no idea how I ended up with so many tokens. I'm pretty sure I only use the second token (read & write to all buckets), so I'd like to turn off, then later remove, all the other tokens for security hygiene. Before I do, I want to make sure that I'm not going to break anything by doing so. But I can't easily tell if I use those other tokens.


__Desired behavior:__
Show the date/time when each token was last used. Or "Never" if has never been used. It's pretty obvious that tokens that haven't been used for a long time, or ever, can be removed.

__Use case:__
Why is this important?

Because as we grow our installed base of InfluxDB users (both OSS and Cloud), it's in our interest to ensure that they keep their databases secure. If a compromised InfluxDB is in the news, it doesn't help our reputation, even if it's user error.

For instance, AWS hasn't helped their reputation by allowing users to be sloppy in their s3 bucket security. Check out all the negative press: https://www.google.com/search?q=aws+s3+bucket+leak

No files, tests, or entry points are named. Locate the token listing and token-use tracking paths, then verify that each token can show its last-used date/time or "Never" when unused.

Written by the indexing model from the issue text.