Improves the existing integraiton tests for `loaded_programs()` and
`loaded_maps()` in consideration for older kernels:
  - Opt for `SocketFilter` program in tests since XDP requires v4.8 and
    fragments requires v5.18.
  - For assertion tests, first perform the assertion, if the assertion
    fails, then it checks the host kernel version to see if it is above
    the minimum version requirement. If not, then continue with test,
    otherwise fail.
    For assertions that are skipped, they're logged in stderr which can
    be observed with `-- --nocapture`.

This also fixes the `bpf_prog_get_info_by_fd()` call for kernels below
v4.15. If calling syscall  on kernels below v4.15, it can produce an
`E2BIG` error  because `check_uarg_tail_zero()` expects the entire
struct to all-zero bytes (which is caused from the map info).

Instead, we first attempt the syscall with the map info filled, if it
returns `E2BIG`, then perform syscall again with empty closure.

Also adds doc for which version a kernel feature was introduced for
better  awareness.

The tests have been verified kernel versions:
  - 4.13.0
  - 4.15.0
  - 6.1.0

Add conversion from u32 to program type, link type, and attach type.
Additionally, remove duplicate match statement for u32 conversion to
`BPF_MAP_TYPE_BLOOM_FILTER` & `BPF_MAP_TYPE_CGRP_STORAGE`.

New error `InvalidTypeBinding<T>` is created to represent when a
parsed/received value binding to a type is invalid.
This is used in the new conversions added here, and also replaces
`InvalidMapTypeError` in `TryFrom` for `bpf_map_type`.

Purpose of this commit is to add detections for whether a field is
available in `ProgramInfo`.
- For `program_type()`, we return the new enum `ProgramType` instead of
  the integer representation.
- For fields that we know cannot be zero, we return `Option<NonZero*>`
  type.
- For `name_as_str()`, it now also uses the feature probe `bpf_name()`
  to detect if field is available or not.
- Two additional feature probes are added for the fields:
  - `prog_info_map_ids()` probe -> `map_ids()` field
  - `prog_info_gpl_compatible()` probe -> `gpl_compatible()` field

With the `prog_info_map_ids()` probe, the previous implementation that
I had for `bpf_prog_get_info_by_fd()` is shortened to use the probe
instead of having to make 2 potential syscalls.

The `test_loaded_at()` test is also moved into info tests since it is
better related to the info tests.

`aya::programs::Programs::prog_type(&self)` now returns `ProgramType`
instead of the generated FFI from aya-obj.

Also previously, `loaded_programs()` could be accessed either through
`aya` or `aya::programs`. To avoid confusion and duplicate export of
the item, the function should now only be exposed through
`aya::programs`.

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.