SSL rampage (#2938)

* Remove stale putative MD2 support

This hasn't worked in a while, presumably since one of our upstream
merges.  Don't bother making it work, since MD2 is generally considered
insecure.

* Land mbedtls 2.16.3-77-gf02988e57

* TLS: remove some dead code from espconn_mbedtls

There was some... frankly kind of scary buffer and data shuffling if
ESP8266_PLATFORM was defined.  Since we don't, in fact, define that
preprocessor symbol, just drop the code lest anyone (possibly future-me)
be scared.

* TLS: espconn_mbedtls: run through astyle

No functional changes

* TLS: espconn_mbedtls: put the file_params on the stack

There's no need to malloc a structure that's used only locally.

* TLS: Further minor tidying of mbedtls glue

What an absolute shitshow this is.  mbedtls should absolutely not
be mentioned inside sys/socket.h and app/mbedtls/app/lwIPSocket.c is not
so much glue as it as a complete copy of a random subset of lwIP; it
should go, but we aren't there yet.

Get rid of the mysterious "mbedlts_record" struct, which housed merely a
length of bytes sent solely for gating the "record sent" callback.

Remove spurious __attribute__((weak)) from symbols not otherwise
defined and rename them to emphasize that they are not actually part of
mbedtls proper.

* TLS: Rampage esp mbedtls glue and delete unused code

This at least makes the shitshow smaller

* TLS: lwip: fix some memp definitions

I presume these also need the new arguments

* TLS: Remove more non-NodeMCU code from our mbedtls

* TLS: drop support for 1.1

Depending on who you ask it's either EOL already or EOL soon, so
we may as well get rid of it now.

app/crypto/digests.c

@@ -37,10 +37,6 @@
 #include <strings.h>
 #include <errno.h>
 
-#ifdef MD2_ENABLE
-#include "ssl/ssl_crypto.h"
-#endif
-
 #ifdef SHA2_ENABLE
 #include "sha2.h"
 #endif
@@ -60,9 +56,6 @@ typedef char ensure_int_and_size_t_same[(sizeof(int)==sizeof(size_t)) ? 0 : -1];
 
 static const digest_mech_info_t hash_mechs[] ICACHE_RODATA_ATTR =
 {
-#ifdef MD2_ENABLE
-   MECH(MD2, _ , MD2_SIZE,  16),
-#endif
    MECH(MD5,   , MD5_DIGEST_LENGTH,  64)
   ,MECH(SHA1,  , SHA1_DIGEST_LENGTH, 64)
 #ifdef SHA2_ENABLE

app/include/lwip/memp_std.h

@@ -52,14 +52,14 @@ LWIP_MEMPOOL(FRAG_PBUF,      MEMP_NUM_FRAG_PBUF,       sizeof(struct pbuf_custom
 #endif /* IP_FRAG && !IP_FRAG_USES_STATIC_BUF && !LWIP_NETIF_TX_SINGLE_PBUF */
 
 #if LWIP_NETCONN
-LWIP_MEMPOOL(NETBUF,         MEMP_NUM_NETBUF,          sizeof(struct netbuf),         "NETBUF")
-LWIP_MEMPOOL(NETCONN,        MEMP_NUM_NETCONN,         sizeof(struct netconn),        "NETCONN")
+LWIP_MEMPOOL(NETBUF,         MEMP_NUM_NETBUF,          sizeof(struct netbuf),         "NETBUF", DMEM_ATTR)
+LWIP_MEMPOOL(NETCONN,        MEMP_NUM_NETCONN,         sizeof(struct netconn),        "NETCONN", DMEM_ATTR)
 #endif /* LWIP_NETCONN */
 
 #if NO_SYS==0
-LWIP_MEMPOOL(TCPIP_MSG_API,  MEMP_NUM_TCPIP_MSG_API,   sizeof(struct tcpip_msg),      "TCPIP_MSG_API")
+LWIP_MEMPOOL(TCPIP_MSG_API,  MEMP_NUM_TCPIP_MSG_API,   sizeof(struct tcpip_msg),      "TCPIP_MSG_API", DMEM_ATTR)
 #if !LWIP_TCPIP_CORE_LOCKING_INPUT
-LWIP_MEMPOOL(TCPIP_MSG_INPKT,MEMP_NUM_TCPIP_MSG_INPKT, sizeof(struct tcpip_msg),      "TCPIP_MSG_INPKT")
+LWIP_MEMPOOL(TCPIP_MSG_INPKT,MEMP_NUM_TCPIP_MSG_INPKT, sizeof(struct tcpip_msg),      "TCPIP_MSG_INPKT", DMEM_ATTR)
 #endif /* !LWIP_TCPIP_CORE_LOCKING_INPUT */
 #endif /* NO_SYS==0 */
 
@@ -82,13 +82,13 @@ LWIP_MEMPOOL(SNMP_VARBIND,   MEMP_NUM_SNMP_VARBIND,    sizeof(struct snmp_varbin
 LWIP_MEMPOOL(SNMP_VALUE,     MEMP_NUM_SNMP_VALUE,      SNMP_MAX_VALUE_SIZE,              "SNMP_VALUE")
 #endif /* LWIP_SNMP */
 #if LWIP_DNS && LWIP_SOCKET
-LWIP_MEMPOOL(NETDB,          MEMP_NUM_NETDB,           NETDB_ELEM_SIZE,               "NETDB")
+LWIP_MEMPOOL(NETDB,          MEMP_NUM_NETDB,           NETDB_ELEM_SIZE,               "NETDB", DMEM_ATTR)
 #endif /* LWIP_DNS && LWIP_SOCKET */
 #if LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC
-LWIP_MEMPOOL(LOCALHOSTLIST,  MEMP_NUM_LOCALHOSTLIST,   LOCALHOSTLIST_ELEM_SIZE,       "LOCALHOSTLIST")
+LWIP_MEMPOOL(LOCALHOSTLIST,  MEMP_NUM_LOCALHOSTLIST,   LOCALHOSTLIST_ELEM_SIZE,       "LOCALHOSTLIST", DMEM_ATTR)
 #endif /* LWIP_DNS && DNS_LOCAL_HOSTLIST && DNS_LOCAL_HOSTLIST_IS_DYNAMIC */
 #if PPP_SUPPORT && PPPOE_SUPPORT
-LWIP_MEMPOOL(PPPOE_IF,      MEMP_NUM_PPPOE_INTERFACES, sizeof(struct pppoe_softc),    "PPPOE_IF")
+LWIP_MEMPOOL(PPPOE_IF,      MEMP_NUM_PPPOE_INTERFACES, sizeof(struct pppoe_softc),    "PPPOE_IF", DMEM_ATTR)
 #endif /* PPP_SUPPORT && PPPOE_SUPPORT */
 
 /*