Reject raw files without padding if discard partial is not set (#374)

We have no code in aare to deal with RawFiles that have missing packets
if they are not padded to full size or frames with packet loss dropped.

Added: 
- check that we don't try to read files that are not supported
- python bindings for frame discard policy

at least we get the check in: 
closes #171

---------

Co-authored-by: AliceMazzoleni99 <alice.mazzoleni@psi.ch>

python/src/bind_Defs.hpp

@@ -95,4 +95,9 @@ void define_defs_bindings(py::module &m) {
         .value("GATED", TimingMode::GATED)
         .value("BURST_TRIGGER", TimingMode::BURST_TRIGGER)
         .value("TRIGGER_GATED", TimingMode::TRIGGER_GATED);
+
+    py::enum_<FrameDiscardPolicy>(m, "FrameDiscardPolicy")
+        .value("NoDiscard", FrameDiscardPolicy::NoDiscard)
+        .value("Discard", FrameDiscardPolicy::Discard)
+        .value("DiscardPartial", FrameDiscardPolicy::DiscardPartial);
 }