[Pre-RFC] `cargo package` should include fewer files by default

kpreid:

Tangential to the rest of the thread, but I think that this should be considered poor practice.

I disagree. We use include_bytes! pretty extensively in RustCrypto by encoding KATs into a custom binary format, including the resulting blob, and parsing it at compile time (see the blobby crate).

What do you propose to use instead? Keep thousands of KAT lines as part of source code? Or use file IO to read KATs at runtime? We want to have compact tests, keep the compile time checks (e.g. that the blobs have expected format) and to be able to execute tests on no_std targets (with some minor tweaking).

Now, I agree that excluding only blobs and thus breaking tests is not correct and should be discouraged. For example, in cmac we exclude both "large" blob and module which uses it.