move all sensor daemons to libexec

Per the organization anti-pattern, executables are expected to be
installed into libexec instead of bin[1].  Update service files and
meson to install there.

[1]: https://github.com/openbmc/docs/blob/master/anti-patterns.md#incorrect-placement-of-executables-in-sbin-usrsbin-or-bin-usrbin

Change-Id: I1eb4003e94b83b09829d63346c2e16a3ff02a3e9
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/src/mctp/meson.build b/src/mctp/meson.build
index 32009c7..d907418 100644
--- a/src/mctp/meson.build
+++ b/src/mctp/meson.build
@@ -5,4 +5,5 @@
     'MCTPEndpoint.cpp',
     dependencies: [default_deps, utils_dep],
     install: true,
+    install_dir: '/usr/libexec/dbus-sensors',
 )