Release v0.3

Notable changes:
- DBus support
- command line client - mconnectctl
- new protocol handlers:
  - share (file, url, text)
  - ping
- Update supported KDE Connect protocol to version 7
  - NOTE: versions < 7 are not supported

Build/dependency/packaging changes:
- dropped OpenSSL in favor of GnuTLS
- replaced autotools with meson
- example configuration files for firewalld are provided in ./extra/firewalld

Tagging as v0.2.1

Marking release 0.2