Made read MMU a non mutable operation.
Added support for CPU description.
Added Display support for CPU.
Extracted type definition for `Instruction`.
Support for diag_gb!() - uses global unsafe approach, which is not problematic for the purpose.
Inline fetch() operation in cpu clock.
Moved pedantic validation up in the CPU.
Fix simple diag issue.
Changed naming of read and write unsafe ops to raw.
New pedantic asserts.
Fix an issue with HDMA destination address prevent CHIP-8 ROM from
working.

Created infrastructure that allows the usage of the serial device to capture the result of the tests.
Then the test is executed agains a pre-defined number of cycles and the result is compared against expectation.

The solution makes use of the chrono module to obtain time and the image module to save PNG files.
The Web version is still pending support for printing.

The image data buffer printing is still pending.
Still a lot of TODOs and edge cases to be solved.

Allowing better directory usage.
Created initial printer file.