Revert all SASL authzid (new feature) commits

- Revert all commits related to the SASL authzid feature since the next
  release will be a patch release, 7.65.1.

Prior to this change CURLOPT_SASL_AUTHZID  / --sasl-authzid was destined
for the next release, assuming it would be a feature release 7.66.0.
However instead the next release will be a patch release, 7.65.1 and
will not contain any new features.

After the patch release after the reverted commits can be restored by
using cherry-pick:

git cherry-pick a14d72c a9499ff 8c1cc36 c2a8d52 0edf690

Details for all reverted commits:

Revert "os400: take care of CURLOPT_SASL_AUTHZID in curl_easy_setopt_ccsid()."

This reverts commit 0edf6907ae.

Revert "tests: Fix the line endings for the SASL alt-auth tests"

This reverts commit c2a8d52a13.

Revert "examples: Added SASL PLAIN authorisation identity (authzid) examples"

This reverts commit 8c1cc369d0.

Revert "curl: --sasl-authzid added to support CURLOPT_SASL_AUTHZID from the tool"

This reverts commit a9499ff136.

Revert "sasl: Implement SASL authorisation identity via CURLOPT_SASL_AUTHZID"

This reverts commit a14d72ca2f.

include/curl/curl.h

@@ -1921,9 +1921,6 @@ typedef enum {
   /* maximum age of a connection to consider it for reuse (in seconds) */
   CINIT(MAXAGE_CONN, LONG, 288),
 
-  /* SASL authorisation identity */
-  CINIT(SASL_AUTHZID, STRINGPOINT, 289),
-
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 

include/curl/typecheck-gcc.h

@@ -309,7 +309,6 @@ _CURL_WARNING(_curl_easy_getinfo_err_curl_off_t,
    (option) == CURLOPT_RTSP_SESSION_ID ||                                     \
    (option) == CURLOPT_RTSP_STREAM_URI ||                                     \
    (option) == CURLOPT_RTSP_TRANSPORT ||                                      \
-   (option) == CURLOPT_SASL_AUTHZID ||                                        \
    (option) == CURLOPT_SERVICE_NAME ||                                        \
    (option) == CURLOPT_SOCKS5_GSSAPI_SERVICE ||                               \
    (option) == CURLOPT_SSH_HOST_PUBLIC_KEY_MD5 ||                             \