Move ftp file server code to common pkg #34724

Job	Run time
Check whether tests need to be run based on diff	21s
Verify docs and spelling	36s
Build Antrea and antctl binaries	12m 59s
Go benchmark test	5m 12s
Golangci-lint (macos-latest)	6m 20s
Golangci-lint (ubuntu-latest)	9m 11s
Integration test	6m 3s
Unit test (ubuntu-latest)	7m 32s
Unit test (windows-2022)	14m 48s
Check tidy, code generation and manifest	4m 8s
Build Antrea Windows binaries	2m 14s
	1h 9m 24s

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