[Improvement] Change install path, add uninstallation script

[nerett]

Description

There were some issues and misunderstandings with home/user/gnu-koryavov/ installation path (e.g. it had conflicts with the same directory when cloning gnu-koryavov repo to the home directory). I decided to change it to home/user/.gnu-koryavov/. This step also resolves possible uninstallation conflicts. I also added uninstall.sh, that removes gnu-koryavov's files from /usr/local/bin/, /tmp/, and /home/user/.gnu-koryavov/.

[nerett]

Checks cannot be passed because this PR changes the installation path