Addtion of info/help icons to data fields

[sjbruce]

Each field represented from a station or as part of the hurricane track could benefit from a small explanation of their purpose and value.

For station data this could be mapped in a dictionary based on standard_names, which each field will have.

For hurricane data there will need to be some work to harmonize these values based on data source as ECCC and IBTRACS will have variations in field names.

There will be some overlap between storm and station data for fields like air pressure, wind speed and the like. Storm data will have some unique fields like wind speed radius, which could certainly benefit from additional explanation and context for users.

[JaredMclellan]

Created a branch to add to the station data: https://github.com/cioos-atlantic/atlantic-hurricane-dashboard/blob/data_field_info/react/data/station/attributes.json

Currently just uses simple hover text to deliver the definition but can change in the future. It's not apparent the definition exists as a hover without prior knowledge so perhaps can add a highlight on hover as well or something similar. Definitions are mapped to a standard name, along with a more human readable name of the variable.