🛠️ [TASK] :`rust/c509-certificate` Cleanup

[bkioshn]

Summary

Cleanup c509 certificate crate

Description

Summary

Cleanup C509 lib

Description

Cleanup the C509 library
Including

• Restructuring the files - renaming the file
• Fix function name following the https://rust-lang.github.io/api-guidelines/naming.html + Add necessary functions
• Add Cbor Encode + Decode helper functions, since right now is hard to track where the error is from
• Refactor test cases
• Check documentation