sancus: start new go package

Signed-off-by: Alejandro Mery <amery@geeks.cl>
gofmt: add helper to call `gofmt` on our .go files

Signed-off-by: Alejandro Mery <amery@geeks.cl>
net: add Listen() function to be smarter on the address string

Signed-off-by: Alejandro Mery <amery@geeks.cl>
net: Add dummy Listener type

for compatibility with the standard `net`

Signed-off-by: Alejandro Mery <amery@geeks.cl>