meson: add necessary subprojects

Add subprojects for all the direct dependencies of the project such
that the project can be built outside of a Yocto SDK on a typical
Linux development system.

  - Update the .gitignore to ignore the subproject source directories.
  - Update the .gitignore to ignore alternative build subdirectory
    names as is typical with most projects in the openbmc organization.
  - Add wrap files for direct dependencies, copied from other
    repositories that already have the same dependencies.
  - Modify the meson.build dependency for libgpiod so that the C++
    bindings are included.
  - Add many missing dependencies throughout.
  - Sort all dependencies alphabetically for consistency.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I0feb6f0f175e6dba0b00a2c2b666eb0801575734
diff --git a/power-supply/meson.build b/power-supply/meson.build
index 0273181..4bf1626 100644
--- a/power-supply/meson.build
+++ b/power-supply/meson.build
@@ -6,9 +6,11 @@
     'power_supply.cpp',
     'record_manager.cpp',
     dependencies: [
+        nlohmann_json_dep,
         phosphor_dbus_interfaces,
         phosphor_logging,
         sdbusplus,
+        sdeventplus,
     ],
     include_directories: '..',
     install: true,