add initial imds module (metadata service querying)
add dinerl:setup/1, which accepts only the Zone argument, and obtains security token data from the instance metadata service
update imds:get_session_token/0 to have same return types as iam:get_session_token/2
wrap calls to lhttpc:request in catch() and increase timeout to match iam module
refactor some common imds request functionality, adjust function names & exports, implement request retries, and add new zone/0 export
add dinerl:setup/0, which uses the zone obtained from the local instance metadata server
update readme to reflect new IMDS functionality
fix non-use of Timeout param
fix call_with_retry usage
fix exports
convert token values to lists
update testcase
add instance_id/0 and public_hostname/0 imds functions
use httpc instead of lhttpc when retrieving imds data
Merge pull request #9 from SemanticSugar/RTB-1768-hologram-hack-day

add option to obtain security tokens from IMDS instead of STS