[4pt] Fetch missions - Fetch data #55

[DanSam5K]

Fetch data from the Missions endpoint (https://api.spacexdata.com/v3/missions) when a user navigates to the Missions section.
Once the data are fetched, dispatch an action to store the selected data in Redux store:

• mission_id
• mission_name
• description

NOTE: Make sure you only dispatch those actions once and do not add data to store on every re-render (i.e. when changing views / using navigation).