pseq: Add base and UCD90320 device monitor classes

Add a power sequencer device monitoring base class and a UCD90320
subclass. Update power controller class to construct and pass device
information to device class.  Update build file to support.

Signed-off-by: Jim Wright <jlwright@us.ibm.com>
Change-Id: Idf3ef53011b23f15841d93795f9f0995892b10b9
diff --git a/phosphor-power-sequencer/src/meson.build b/phosphor-power-sequencer/src/meson.build
index 8f74c7e..4ea4b9c 100644
--- a/phosphor-power-sequencer/src/meson.build
+++ b/phosphor-power-sequencer/src/meson.build
@@ -8,6 +8,7 @@
     'power_control_main.cpp',
     'power_control.cpp',
     'power_interface.cpp',
+    'ucd90320_monitor.cpp',
     dependencies: [
         libgpiodcxx,
         phosphor_logging,