v3 YAML config: require `$default-byte-order` property
v3 YAML config: require `$default-byte-order` property

CTF 1.8 consumers require the `trace` block's `byte_order` property, so
let's require it in barectf too for the moment.

We can relax this requirement later if possible.

Signed-off-by: Philippe Proulx <2096628897b40c93960fdd9e24c9c883a54d4fe9@gmail.com>

efficios/barectf,efficios/barectf