feat(cli): extend duration to longer units (#15040)

This PR is a proposal to improve the situation described in #14750 

For some precise commands - we would like to be able to use durations
bigger than hours, minutes..

This PR extends the Duration proposed by Go with : 
- `d` - a day or 24hours.
- `y` - a year or 365 days.

I also removed the default value for lifetime and instead fetch the
maxLifetime value from codersdk - so by default if no value set we use
the value defined in the config.

docs/reference/cli/tokens_create.md

@@ -16,9 +16,8 @@ coder tokens create [flags]
 
 |             |                                    |
 | ----------- | ---------------------------------- |
-| Type        | <code>duration</code>              |
+| Type        | <code>string</code>                |
 | Environment | <code>$CODER_TOKEN_LIFETIME</code> |
-| Default     | <code>720h0m0s</code>              |
 
 Specify a duration for the lifetime of the token.