Use token file on disk to fetch tokens

[m0dular]

This commit changes the retrieve_token() function to use an admin token
on disk. This allows it to be used as a deferred function where it will
be run on agents instead of the primary server.

Also fixes an issue where Dir.home would throw an error when running via
a service.

[puppet-community-rangefinder]

influxdb::retrieve_token is a function

that may have no external impact to Forge modules.

This module is declared in 0 of 578 indexed public Puppetfiles.

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Exact matches are those that we can positively identify via namespace and the declaring modules' metadata. Non-namespaced items, such as Puppet 3.x functions, will always be reported as near matches only.

[MartyEwings]

This appears to work and cause no ill effects,

I assume we have to modify operational dashboards to consume this?

[m0dular]

Yes, we'll use it with Deferred so that agents can use it during catalog application.