build: tidy-up MSVC CRT warning suppression macros

- curl_setup.h: replace `_CRT_SECURE_NO_DEPRECATE` with
  `_CRT_SECURE_NO_WARNINGS`, which seems to be the preferred,
  more recent macro for this. Also syncing with libssh2.
  They are equivalent for curl sources with the supported compilers.
- cmake: stop setting `_CRT_SECURE_NO_DEPRECATE` globally for examples.
- examples: suppress CRT deprecation warnings on a per-file basis.
  To make it work when compiling examples out of curl's build systems.
  Use `_CRT_SECURE_NO_WARNINGS`.
- examples: document the functions requiring `_CRT_SECURE_NO_WARNINGS`.
- examples/block_ip: delete superfluous `_CRT_SECURE_NO_WARNINGS`.
- examples/block_ip: limit `_CRT_NONSTDC_NO_DEPRECATE` to MSVC.
- examples/log_failed_transfers: fix to set `_CRT_SECURE_NO_WARNINGS`
  before headers and limit to MSVC.
- curl_setup.h: document which SDKs support `_CRT_NONSTDC_NO_DEPRECATE`.

Closes #19175

docs/examples/CMakeLists.txt

@@ -83,8 +83,7 @@ foreach(_target IN LISTS COMPLICATED_MAY_BUILD check_PROGRAMS _all)  # keep 'COM
     add_dependencies(curl-examples ${_target_name})
   endif()
   target_link_libraries(${_target_name} ${LIB_SELECTED} ${CURL_NETWORK_AND_TIME_LIBS} ${_more_libs})
-  target_compile_definitions(${_target_name} PRIVATE "CURL_NO_OLDIES"
-    "$<$<BOOL:${WIN32}>:WIN32_LEAN_AND_MEAN>" "$<$<BOOL:${MSVC}>:_CRT_SECURE_NO_DEPRECATE>")
+  target_compile_definitions(${_target_name} PRIVATE "CURL_NO_OLDIES" "$<$<BOOL:${WIN32}>:WIN32_LEAN_AND_MEAN>")
   set_target_properties(${_target_name} PROPERTIES OUTPUT_NAME "${_target}" PROJECT_LABEL "Example ${_target}" UNITY_BUILD OFF)
 endforeach()