FS-8369 Debian8/CentOS7 systemd installer additions

After builing Freeswitch this makes actually run it easy by offering
an installer script.

* Changes to configure.ac to detect Debian8/CentOS 7 and create installer script
* Changes to build/Makefile.am to display the option
* Added init directory with templates and other files
* Deleted outdated build/freeswitch.service and tmpfiles.conf
* Unit file based on the latest systemd service file FS-8194
* Won't interfere with other platforms (afaik)
* Supports ./configure --prefix=
* Detects if Debian8/CentOS7 use systemd
* Can be used with a user with sudo permissions

build/Makefile.am

@@ -1,5 +1,6 @@
 MK=`echo $(MAKE) | $(AWK) '{printf "%5s\n", $$0}' `
 
+
 all:
 	@echo " +---------- FreeSWITCH Build Complete ----------+"
 	@echo " + FreeSWITCH has been successfully built.       +"
@@ -54,6 +55,13 @@ install:
 	@echo " +       Install/Re-install default config:        +"
 	@echo " +       ----------------------------------        +"
 	@echo " +               $(MK) samples                     +"
+if KNOWN_INIT
+	@echo " +                                                 +"
+	@echo " +       Install init scripts:                     +"
+	@echo " +       ---------------------                     +"
+	@echo " +                                                 +"
+	@echo " +       init/install_systemd.sh                   +"
+endif
 	@echo " +                                                 +"
 	@echo " +                                                 +"
 	@echo " +       Additional resources:                     +"

build/freeswitch-tmpfiles.conf

@@ -1 +0,0 @@
-d /run/freeswitch 0750 freeswitch daemon -

build/freeswitch.service

@@ -1,17 +0,0 @@
-[Unit]
-Description=FreeSWITCH
-After=syslog.target network.target
-After=postgresql.service postgresql-9.3.service postgresql-9.4.service mysqld.service httpd.service
-
-[Service]
-User=freeswitch
-EnvironmentFile=-/etc/sysconfig/freeswitch
-# RuntimeDirectory is not yet supported in CentOS 7. A workaround is to use /etc/tmpfiles.d/freeswitch.conf
-#RuntimeDirectory=/run/freeswitch
-#RuntimeDirectoryMode=0750
-WorkingDirectory=/run/freeswitch
-ExecStart=/usr/bin/freeswitch -nc -nf $FREESWITCH_PARAMS
-ExecReload=/usr/bin/kill -HUP $MAINPID
-
-[Install]
-WantedBy=multi-user.target