build: add wrapfiles for dependencies

Add wrapfiles for all dependencies and update meson.build
files to ensure dependencies are requested in all cases.
This enables out-of-bitbake/out-of-sdk builds for this
repository and enables it to be used as a meson subproject.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I0f2f7eed98f7f7555cafefc2605e1031a7f0adaf
diff --git a/subprojects/sdeventplus.wrap b/subprojects/sdeventplus.wrap
new file mode 100644
index 0000000..085bb5e
--- /dev/null
+++ b/subprojects/sdeventplus.wrap
@@ -0,0 +1,3 @@
+[wrap-git]
+url = https://github.com/openbmc/sdeventplus.git
+revision = HEAD