Add support to configure wind download for each scanner

[dlnorgaard]

The new SFTP server has wind files available by volcano. However, wind download configuration is currently under global configurations, so it is not possible to download multiple files if scanners for more than one volcano is configured in the software.

[christophkern]

This feature would be very useful. At OVSICORI, data are coming into the observatory from Poas, Turrialba, and Rincon de la Vieja volcanoes. However, we can only configure wind downloads for 1 volcano, so the other two will use wind from an incorrect location in their analyses...
A temporary workaround could be to run 3 instances of the NOVAC Program, one for each volcano. But the NOVAC Program checks for other instances on startup and doesn't allow more than one instance to run at a time. Is this behavior necessary?