Add system_state dbus property

Add system_state property to keep track of the system
state across reboots.
Include the generated settings_file.py since some build
machines cannot have the yaml python module installed. This
file will be removed once the code is ported to C in the next rework.
Add the path where the settings will be stored in bmc:
/var/lib/obmc/
Address review comments from the initial commit.
diff --git a/settings_file.py b/settings_file.py
index 85f04f0..e05bc31 100644
--- a/settings_file.py
+++ b/settings_file.py
@@ -1,2 +1,2 @@
 #!/usr/bin/python -u
-SETTINGS={'host': {'bootflags': {'default': '0000000000', 'type': 's', 'name': 'boot_flags'}, 'powercap': {'name': 'power_cap', 'min': 0, 'default': 0, 'max': 1000, 'type': 'i', 'unit': 'watts'}}}
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+SETTINGS={'host': {'bootflags': {'default': '0000000000', 'type': 's', 'name': 'boot_flags'}, 'powercap': {'name': 'power_cap', 'min': 0, 'default': 0, 'max': 1000, 'type': 'i', 'unit': 'watts'}, 'sysstate': {'default': '', 'type': 's', 'name': 'system_state'}}}
\ No newline at end of file