Return NTP offset information from get state

[#60787120]
introduce external blobstore

 * Expect blobstore to implement valid, searches in path for external and s3 commands

Signed-off-by: caleb miles <cmiles@pivotallabs.com>
Search for blobstore provider in PATH

Signed-off-by: caleb miles <cmiles@pivotallabs.com>
Go agent dummy infrastructure loads external settings from json
[#63324820]
Add error handling to dummy infrastructure setting json parsing
[#63324820]
Change blobstore interface to return error for validate

This is preperation to remove ApplyOptions and pass options into constructor

Signed-off-by: Jeffrey Peckham <peckham@pivotallabs.com>
Remove ApplyOptions and pass blobstore options into constructor

Validate() now returns the error originally returned by ApplyOptions

Signed-off-by: Jeffrey Peckham <peckham@pivotallabs.com>
Adding final release for build 1744