[graceful reboot] Rename the platform_reboot to the pre_reboot_hook, remove the sysfs power cycle (#18324)

**DEPENDS ON: [[graceful reboot] Add the pre_reboot_hook script execution, add the watchdog arm before the reboot](sonic-net/sonic-utilities#3203

#### Why I did it
Add support for the `graceful reboot` instead of  the `sysfs power cycle` to avoid filesystem corruption 

### How I did it
Rename the `platform_reboot` script to the `pre_reboot_hook`.
Remove the sysfs power cycle function, from now on the Debian reboot (`/sbin/reboot`) will be executed instead of the sysfs power cycle.

#### How to verify it
1. Start watching logs by using `show log -f` and `journalctl -p debug -f`
2. Execute the `reboot` command from the switch CLI
3. Check in logs that all systemd services terminated

Author: vadymhlushko-mlnx

device/mellanox/x86_64-mlnx_lssn2700-r0/platform_reboot

@@ -0,0 +1 @@
+../x86_64-mlnx_msn2700-r0/pre_reboot_hook

device/mellanox/x86_64-mlnx_lssn2700-r0/pre_reboot_hook

@@ -0,0 +1 @@
+../x86_64-mlnx_msn2700-r0/pre_reboot_hook

device/mellanox/x86_64-mlnx_msn2010-r0/platform_reboot

@@ -0,0 +1 @@
+../x86_64-mlnx_msn2700-r0/pre_reboot_hook

device/mellanox/x86_64-mlnx_msn2010-r0/pre_reboot_hook

@@ -0,0 +1 @@
+../x86_64-mlnx_msn2700-r0/pre_reboot_hook

device/mellanox/x86_64-mlnx_msn2100-r0/platform_reboot

@@ -0,0 +1,34 @@
+#!/bin/bash
+
+# Copyright (c) 2020-2023 NVIDIA CORPORATION & AFFILIATES.
+# Apache-2.0
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+declare -r EXIT_SUCCESS=0
+declare -r EXIT_ERROR=1
+
+declare -r PENDING_COMPONENT_FW="/usr/bin/install-pending-fw.py"
+declare -r FW_UPGRADE_SCRIPT="/usr/bin/mlnx-fw-upgrade.sh"
+
+
+${FW_UPGRADE_SCRIPT} --upgrade --verbose
+EXIT_CODE=$?
+if [[ ${EXIT_CODE} != ${EXIT_SUCCESS} ]]; then
+    echo "Failed to burn MLNX FW: errno=${EXIT_CODE}"
+    exit ${EXIT_ERROR}
+fi
+
+${PENDING_COMPONENT_FW}
+
+exit ${EXIT_SUCCESS}