loadsa updates

Supersedes !31 (closed) !40 (closed) !45 (closed)

• progress bars for scanning and building packages!
• config init fix: Fixes #29 (closed) #31 (closed)
• adds support for pkgbuilds/repos.yml and a local-only repo: Fixes #28 (closed)
• uses kupfer-config --user to enable systemd user services for voicecalls
• json export for devices and flavours and nice, colourful list output