Every submodule under the 'crypto' directory was exported-imported
even if a handful of functions where actually needed.
We now only export entire modules behind default exports if it makes
sense for readability and if the different submodules would be
imported together anyway (e.g. `cipherMode` exports are all needed
by the SEIPD class).
We've also dropped exports that are not used outside of the crypto modules,
e.g. pkcs5 helpers.
Mocha v10 requires the lib to be esm compliant.
ESM mandates the use of file extensions in imports, so to minimize the
changes (for now), we rely on the flag `experimental-specifier-resolution=node`
and on `ts-node` (needed only for Node 20).
Breaking changes:
downstream bundlers might be affected by the package.json changes depending on
how they load the library.
NB: legacy package.json entrypoints are still available.
- Use PascalCase for classes, with uppercase acronyms.
- Use camelCase for function and variables. First word/acronym is always
lowercase, otherwise acronyms are uppercase.
Also, make the packet classes' `tag` properties `static`.
