long story short, here’s a quick and simple way how to remove the anniversary garage, if you (like me) don’t like it, by Korney36 on RU forums.
Step 1: go to the World_of_Tanks\res\packages folder
Step 2: find three files: hangar_premium.pkg, hangar_premium_15aug.pkg and hangar_premium_15bday.pkg
Step 3: copy the hangar_premium.pkg over the content of hangar_premium_15aug.pkg and over the content of hangar_premium_15bday.pkg (so you will have the hangar_premium.pkg file in 3 different copies, including the original)
Step 4: Profit!
Tested it myself, works.