update the README with the latest v0.13 - v1.1 agent settings

[lhoss]

some notes:

• PR only updating the README for additions done in https://github.com/dj-wasabi/ansible-telegraf/pull/16
• only precision is now missing, all the other settings are now configurable ** I was not sure what default I'ld set (the best would probably be to omit setting it, if not set by the user)

Update: Could we 'release' a role version/tag (0.6.0 ?) 👍

ps: Seems plenty of other features were added in other config parts, like fieldpass, fielddropin https://github.com/influxdata/telegraf/blob/master/docs/CONFIGURATION.md#processor-configuration. For now I can live with a basic config, but I am definitely considering my idea of supporting to deploy a (fully) custom telegraf.conf (template) , so there's no need to always keep updating the role with the latest new config features/settings

[dj-wasabi]

Thanks! Will create a 0.6.0 release today.

And keep the PR's coming if you think changes are needed to make the role(s) better. 👍