Sentinel Hub QGIS Plugin v1.0

First version of the plugin to also support QGIS 3.0.

List of changes:

• added support for QGIS 3.0,
• functionality to set custom bounding box for image download,
• Sentinel Hub instance id and download folder are now saved locally in QGIS settings,
• improved message and error handling,
• names of downloaded files are now different,
• code style changes,
• various minor changes.