RFC 9177: Add in Q-Block support

[mrdeep1]

examples/client.c: examples/coap-server.c:

Add in Q-Block intelligence.

include/coap2/block.h include/coap2/coap_block_internal.h include/coap2/coap_event.h

Add in Q-Block references. Add in new functions coap_block_check_q_block1_xmit() coap_block_check_q_block2_xmit() coap_send_q_blocks() coap_send_q_block1() coap_send_q_block2() coap_block_drop_resp_q_block_xmit() coap_block_drop_resp_q_block2_crcv()

include/coap2/coap_session.h:

Add in new Congestion Control defaults and ability to configure them.

include/coap2/coap_subscribe_internal.h: include/coap2/resource.h:

Support Q-Block2 as well for subscriptions.

include/coap2/pdu.h:

Add in the new options.

libcoap-2.map: libcoap-2.sym:

Expose external Congestion Control functions.

man/coap-client.txt.in: man/coap-server.txt.in: man/coap_block.txt.in: man/coap_handler.txt.in:

Add in Q-Block information.

src/block.c:

Add in the new functions to support Q-Block.

src/coap_debug.c:

Output the new options as appropriate.

src/coap_io.c:

Check for Q-Block transmission timeouts.

src/coap_session.c:

Add in the Congestion Control support.

src/net.c: src/pdu.c: src/resource.c:

Add in Q-Block support.