* remove lwip-v1.4 specific code
* ditto
* ditto
* fix ip4_addr definition
* CI: change debug builds to use IPv6, remove regular IPv6 builds
* ditto
* split pio CI in four (because they last twice the time of the other builds)
* remove option from pio
* remove lwIP-1.4 from doc
* restore pio CI splitting
* fix CI debug6 script
* ditto
* lwip2: better handling of ipv4_addr/t type + 3 sntp servers
* bump lwip2 version
* Only with FEATURES=1: 3 sntp servers and AutoIP enabled (169.254 when dhcp server fails)
* Only with FEATURES=1: 3 sntp servers and AutoIP enabled (169.254 when dhcp server fails)
* local CI runner: select build type
* new ipv4_addr/t definition makes things easier for IPAddress
* update local CI runner
* lwip2 changes
* lwip2: port esp-ping and espconn