Refactor ported files

[Jacherr]

Some files in the assyst2 codebase are direct ports of their legacy counterparts. One notable example is assyst-core/src/bad_translator.rs. However, this implementation probably does not take advantage of newer features in the rewrite and as such can probably be refactored heavily to more closely match the new conventions that the rewrite provides. This also applies to any other ported files and functions (such as a lot of command execution functions).