Extend polling to 120 seconds to address apparent API Rate Limit

Extended the polling interval to 120 seconds to address the apparent API Rate Limit in issue #46

Fix issue with latest launch payload data missing

Handle issue where latest launch payload may be missing from the source SpaceX API data. Fixed #45

Catch remaining Payload data issues.

Fix remaining issues related to payload data missing from source. (#40)

Fix issue when Payload data is missing.

Fix issue when payload data is missing from source data. Fixes #40

Remove deprecated state attributes

Remove the deprecated state attributes.

Fix repeating error related to Null data returned for latest launch

Fixes issue #33 related to null data being returned by the SpaceX API for the latest launch details.

Remove Connection Class from Discovery Flow

Remove deprecated Connection Class from the integration.

Added version key to manifest file

Added version key to manifest file.

Fix issue with Next Rocket being NoneType

Fix an issue where the next rocket was returning a NoneType error.

More mission details, fixes issue with null cores data

Two fixes included:

• fixes an issue where an error occurred if the cores data from the API was null
• adds attributes details2 and details3 to handle longer mission details blocks