memory leak in devices via peers (and sk)

[stef]

making a simple example and running it with asan, i see that even though i free all sessions using Noise_XK_session_free() and then all devices using Noise_XK_device_free() some memory leaks that is allocated by noise-star, it seems the biggest culprit is the peers, but it also seems that the device serialization key (sk) is not freed in Noise_XK_device_free()

==13784==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 216 byte(s) in 9 object(s) allocated from:
    #0 0x55ce3d2ff9cf in __interceptor_malloc (src/test+0xbc9cf) (BuildId: cfcdfcff81501c2bb9e6d42569c83ce41bc5e6ea)
    #1 0x7fa80bcd32a2 in Noise_XK_device_add_peer src/XK.c:907

Direct leak of 96 byte(s) in 3 object(s) allocated from:
    #0 0x55ce3d2ff3a7 in __interceptor_calloc (src/test+0xbc3a7) (BuildId: cfcdfcff81501c2bb9e6d42569c83ce41bc5e6ea)
    #1 0x7fa80bcd2c1f in Noise_XK_device_create src/XK.c:429
    #2 0x55ce3d24c835 in main src/test.c:705
    #3 0x7fa80ba0e6c9 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

Indirect leak of 288 byte(s) in 9 object(s) allocated from:
    #0 0x55ce3d2ff3a7 in __interceptor_calloc (src/test+0xbc3a7) (BuildId: cfcdfcff81501c2bb9e6d42569c83ce41bc5e6ea)
    #1 0x7fa80bcd323f in Noise_XK_device_add_peer src/XK.c:854

Indirect leak of 108 byte(s) in 9 object(s) allocated from:
    #0 0x55ce3d2ff3a7 in __interceptor_calloc (src/test+0xbc3a7) (BuildId: cfcdfcff81501c2bb9e6d42569c83ce41bc5e6ea)
    #1 0x7fa80bcd334c in Noise_XK_device_add_peer src/XK.c:880

Indirect leak of 72 byte(s) in 9 object(s) allocated from:
    #0 0x55ce3d2ff9cf in __interceptor_malloc (src/test+0xbc9cf) (BuildId: cfcdfcff81501c2bb9e6d42569c83ce41bc5e6ea)
    #1 0x7fa80bcd3292 in Noise_XK_device_add_peer src/XK.c:902