Split Ftp plugin into Ftp and FtpServer #3425

Job	Run time
coverage (ubuntu-20.04)	5m 13s
ubuntu-22.04 (style and proto check)	1m 15s
Ubuntu/Debian packaging (Ubuntu 20.04)	10m 4s
ubuntu-20.04 (package, non-mavsdk_server)	8m 9s
ubuntu-20.04 (mavsdk_server, superbuild)	40m 42s
ubuntu-22.04 (package, non-mavsdk_server)	6m 20s
ubuntu-22.04 (mavsdk_server, superbuild)	40m 1s
alpine 3.16.0 (musl)	14m 0s
linux-armv6	4m 57s
ubuntu-20.04 (mavsdk, hunter)	7m 10s
linux-armv7	4m 46s
ubuntu-20.04 (non-mavsdk_server, non-superbuild)	5m 30s
linux-arm64	6m 25s
android-arm	7m 43s
linux-armv6-musl	12m 18s
android-arm64	6m 31s
ios	9m 24s
android-x86	7m 41s
ios_simulator	9m 20s
linux-armv7l-musl	12m 24s
android-x86_64	7m 20s
linux-arm64-musl	15m 43s
macOS	43m 58s
Windows	1h 39m 31s
macOS-framework	44m 2s
iOS XCFramework	0s
	7h 10m 27s

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