Use Pinpit plugin for packaging

.gitlab-ci.yml

README.md

briar-desktop/build.gradle.kts

briar-desktop/src/packagingResources/linux/deb/copyright

briar-desktop/src/packagingResources/linux/deb/postinst

briar-desktop/src/packagingResources/linux/deb/preinst

briar-desktop/src/packagingResources/linux/deb/prerm

briar-desktop/src/packagingResources/linux/launcher.desktop

briar-desktop/src/packagingResources/windows/.gitignore

briar-desktop/src/packagingResources/windows/banner.bmp

briar-desktop/src/packagingResources/windows/banner.svg

briar-desktop/src/packagingResources/windows/convert.sh

briar-desktop/src/packagingResources/windows/dialog.bmp

briar-desktop/src/packagingResources/windows/dialog.svg

gradle.properties

utils/finalize-deb.sh