build: enable subproject-based build

* Move existing phosphor-logging.wrap to the subprojects directory.
* Add wrap files for all openbmc dependencies.
* Fix up meson.build files to utilize subproject dependencies and follow
  Meson conventions for dependency naming.
* Ensure wrap files are not ignored by .gitignore.

Tested: Built on a typical Linux development system and 'ninja test'
        passed.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I167911f045ee1f27cc69bcba7be185762844a030
diff --git a/.gitignore b/.gitignore
index 44bbe67..d7a8fcb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 ### Meson ###
 # subproject directories
 /subprojects/*
+!/subprojects/*.wrap
 
 # build directory
 build*/*