More method and constructor constness

In several data representations within `wire` we would benefit from additional `const` qualifiers. Especially for setting up static data this could greatly simplify code, instead of requiring use of `lazy_static!` or other shenenigans.

Look at the `wire` module for data representations that could benefit from `const` qualifiers, especially for static data setup. Identify methods and constructors that can be made `const` to simplify code and reduce reliance on `lazy_static!`. Check existing tests to ensure changes don't break functionality.

Scritto dal modello di indicizzazione a partire dal testo della issue.