aya,int-test: revamp MapInfo be more friendly with older kernels

Adds detection for whether a field is available in `MapInfo`:
- For `map_type()`, we treturn new enum `MapType` instead of the integer
  representation.
- For fields that can't be zero, we return `Option<NonZero*>` type.
- For `name_as_str()`, it now uses the feature probe `bpf_name()` to
  detect if field is available.
  Although the feature probe checks for program name, it can also be
  used for map name since they were both introduced in the same commit.

aya-log/src/lib.rs

@@ -150,7 +150,7 @@ impl EbpfLogger {
  None => false,
  })
  .ok_or(Error::MapNotFound)?;
- let map = MapData::from_id(map.id()).map_err(Error::MapError)?;
+ let map = MapData::from_id(map.id().unwrap().get()).map_err(Error::MapError)?;
 
  Self::read_logs_async(Map::PerfEventArray(map), logger)?;
 

aya-obj/src/obj.rs

@@ -81,7 +81,10 @@ impl Features {
  }
  }
 
- /// Returns whether BPF program names are supported.
+ /// Returns whether BPF program names and map names are supported.
+ ///
+ /// Although the feature probe performs the check for program name, we can use this to also
+ /// detect if map name is supported since they were both introduced in the same commit.
  pub fn bpf_name(&self) -> bool {
  self.bpf_name
  }