Fix debian package lintian warnings

See the stretch build and the ubuntu zesty build for details

• W: bitmask source: diff-contains-git-control-dir .git
• W: bitmask source: debhelper-but-no-misc-depends bitmask-js bitmask-mail bitmask-mua
• W: bitmask source: debian-rules-sets-DEB_BUILD_OPTIONS MR pending
• W: virtual-package-depends-without-real-package-depends depends: polkit-1-auth-agent MR pending
• W: menu-command-not-in-package MR pending
• W: duplicate-short-description MR pending
• W: bitmask-core: binary-without-manpage usr/bin/bitmaskctl
• W: bitmask-core: binary-without-manpage usr/bin/bitmaskd
• W: bitmask-qt: binary-without-manpage usr/bin/bitmask
• W: bitmask-core: pkg-not-in-package-test bitmask usr/share/menu/bitmask-core
• W: bitmask-chromium: empty-binary-package