Consistent naming for context gettable param queries .

All instances of EVP_*_CTX_gettable_params functions have been renamed
to EVP_*_gettable_ctx_params.  Except for the EVP_MD ones which were changed
already.

These functions do not take EVP_*_CTX arguments so their prior naming was
misleading.

Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10052)
diff --git a/apps/kdf.c b/apps/kdf.c
index c230430..35cc0db 100644
--- a/apps/kdf.c
+++ b/apps/kdf.c
@@ -96,7 +96,7 @@
     if (opts != NULL) {
         int ok = 1;
         OSSL_PARAM *params =
-            app_params_new_from_opts(opts, EVP_KDF_CTX_settable_params(kdf));
+            app_params_new_from_opts(opts, EVP_KDF_settable_ctx_params(kdf));
 
         if (params == NULL)
             goto err;