Revert "Add key management system" (978f869b99) & later commits

The patch needs test cases, reorganization, and cfbot testing.
Technically reverts commits 5c31afc49d..e35b2bad1a (exclusive/inclusive)
and 08db7c63f3..ccbe34139b.

Reported-by: Tom Lane, Michael Paquier

Discussion: https://postgr.es/m/E1ktAAG-0002V2-VB@gemulon.postgresql.org

src/backend/postmaster/postmaster.c

@@ -100,7 +100,6 @@
 #include "common/file_perm.h"
 #include "common/ip.h"
 #include "common/string.h"
-#include "crypto/kmgr.h"
 #include "lib/ilist.h"
 #include "libpq/auth.h"
 #include "libpq/libpq.h"
@@ -232,7 +231,6 @@ static int	SendStop = false;
 
 /* still more option variables */
 bool		EnableSSL = false;
-int			terminal_fd = -1;
 
 int			PreAuthDelay = 0;
 int			AuthenticationTimeout = 60;
@@ -689,7 +687,7 @@ PostmasterMain(int argc, char *argv[])
 	 * tcop/postgres.c (the option sets should not conflict) and with the
 	 * common help() function in main/main.c.
 	 */
-	while ((opt = getopt(argc, argv, "B:bc:C:D:d:EeFf:h:ijk:lN:nOPp:r:R:S:sTt:W:-:")) != -1)
+	while ((opt = getopt(argc, argv, "B:bc:C:D:d:EeFf:h:ijk:lN:nOPp:r:S:sTt:W:-:")) != -1)
 	{
 		switch (opt)
 		{
@@ -780,10 +778,6 @@ PostmasterMain(int argc, char *argv[])
 				/* only used by single-user backend */
 				break;
 
-			case 'R':
-				terminal_fd = atoi(optarg);
-				break;
-
 			case 'S':
 				SetConfigOption("work_mem", optarg, PGC_POSTMASTER, PGC_S_ARGV);
 				break;
@@ -1332,11 +1326,6 @@ PostmasterMain(int argc, char *argv[])
 	 */
 	RemovePgTempFiles();
 
-	InitializeKmgr();
-
-	if (terminal_fd != -1)
-		close(terminal_fd);
-
 	/*
 	 * Initialize stats collection subsystem (this does NOT start the
 	 * collector process!)