The existing parser made too many assumptions with SEG-Y in mind threaded
throughout its code.
This implements a fully format-agnostic binary blob parser, where it's up
to the Input_file or Output_file to marshall the expected data into the
parser.

The Rule structure has been removed from the code, and from the Trace_metadata
structure. The Trace_metadata structure now only knows about metadata keys,
metadata types, and data counts, which it receives from the file layer.
It knows nothing about parsing.

Change Log:
* Replace Rule structure with Blob_parser
* Removing parsing logic from Trace_metadata
* Put parsing logic entirely in the file layer
* Refactored utils::types, removing unused Type::Index and Type::Copy
* Refactored Trace_metadata_key and segy::Trace_header_offsets