* Move config-dependent methods to separate package
In order to reuse the fetching and file creation part of the
bootstrap package, move the code that would cause cyclical
dependencies to a different package.
* Export needed bootstrap methods and variables
Also add back validating persisted config and update tests.
* Add support to check for just management token
Add a new method that fetches the bootstrap configuration only if
there isn't a valid management token file instead of checking for
all the hcp-config files.
* Pass data dir as a dependency to link controller
The link controller needs to check the data directory for
the hcp-config files.
* Fetch bootstrap config for token in controller
Load the management token when reconciling a link resource, which will
fetch the agent boostrap configuration if the token is not already
persisted locally. Skip this step if the cluster is in read-only mode.
* Validate resource ID format in link creation
* Handle unauthorized and forbidden errors
Check for 401 and 403s when making GNM requests, exit bootstrap fetch
loop and return specific failure statuses for link.
* Move test function to a testing file
* Log load and status write errors
Melissa Kam