Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
Input challenges and returned messages are now in binary.
Conversions from/to base64 are performed by callers (currently curl_sasl.c
and http_ntlm.c).
Closes#6654
OAUTHBEARER tokens were incorrectly generated in a format similar to
XOAUTH2 tokens. These changes make OAUTHBEARER tokens conform to the
RFC7628.
Fixes: #2487
Reported-by: Paolo Mossino
Closes https://github.com/curl/curl/pull/3377
