Features:
* Add prepare() function to initialize camera plugin (1563).
Bugfixes:
* ftp: remove mavlink header install (1565).
* Fix some scope issues in mavlink_commands.cpp (1560).
* Fix list_photos (1559).
* fixed mavsdk_server library versioning (1550).
* Fix possible setting options list when camera uses exclusions (1548).
* core: fix calling callback multiple times (1545).
* Fix stop in mavsdk_server (1535).
* Fix mission download (1528).
Enhancements:
* Add `autopilot_server` example, utilising server plugins (1567).
* Ardupilot mission handling and vehicle type checking (1562).
* docker: remove perl dependency (1558).
* core: add API to get MAVLink component IDs (1557).
* Small command fixes (1556).
* plugins: action: change to Hold mode before sending DO_REPOSITION (1553).
* Add health support for ardupilot (1552).
* core: refactor MAVLink command queue (1546).
* Do not report -1 as a current mission item (1544).
* Fix small warnings reported by clang (1543).
* Fix clang warnings (1538).
* Improve connection and corresponding logging (1533).
* Update proto submodule (1530).
* Update dependencies (1529).
Contributors:
bazfp, DaRavenox, JonasVautherin, julianoes, mattes-bru, TSC21