Release 2.9.0

The following issues have been fixed with this release:

• Hubhop needs quality assurance checks before accepting a new event #62
• Hubhop potentiometer tool does not allow negative sign to be entered first #65
• Delete duplicate categories for iFly 737 Max8 #67

Additionally, the release contains the following fixes (which don't have an issue on Github):

• Add possibility for query URL (e.g. ?vendor=fenix)
  You can now copy and paste the URL to pass a search to users like this: https://hubhop.mobiflight.com/presets/?vendor=Asobo&aircraft=Airliner&system=EFIS&presetType=Input&search=bar
• Check if filter/search can be made case sensitive
  Added correct sorting based on case (iFly is now next to IniBuilds)