meson: Add boost dependency

Copied the bits and pieces from bmcweb.

Change-Id: I6ce919ac5f30d9c814df6e96ba8b579115c82a4b
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/subprojects/packagefiles/boost/meson.build b/subprojects/packagefiles/boost/meson.build
new file mode 100644
index 0000000..b5dea0a
--- /dev/null
+++ b/subprojects/packagefiles/boost/meson.build
@@ -0,0 +1,9 @@
+project('boost',
+    'cpp',
+    version : '1.81.0',
+    license : 'Boost'
+)
+
+boost_dep = declare_dependency(
+    include_directories : include_directories('.'),
+)