EVP_DecodeUpdate() should not produce padding zeros to the decoded output (Fixes...

EVP_DecodeUpdate() should not produce padding zeros to the decoded output (Fixes #26677)

EVP_DecodeUpdate() should not produce zeros for input padding `=` signs to avoid writing to non-allocated memory regions.

To achieve this:
- Add `eof` parameter to `evp_decodeblock_int` function in `openssl/crypto/evp`. The parameter should either contain the number of the input padding characters to ignore or `-1` if the function has to count them.
- Use precalculated `eof` in `EVP_DecodeUpdate` to fix its behaviour.
- Use `eof = -1` in `EVP_DecodeFinal` to count it in `evp_decodeblock_int`.
- Do not ignore padding in `EVP_DecodeBlock` (`eof = 0`) because it should write padding zeros according to the documentation.
- Add the HISTORY section to EVP_EncodeInit documentation to describe the fix.

Other changes:
- Update AUTHORS.md
- Update the copyright date in the documentation.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Viktor Dukhovni <viktor@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/26678)