PLDM: Implementing Phosphor-Logging/LG2 logging

This commit adds changes in PLDM for implementing
structured LG2 logging, thereby moving away from
std::cout/cerr practice of logging which are
output streams and not logging mechanism.

PLDM now can make use of lg2 features like accurate
CODE LINE Number and CODE_FUNCTION Name and better
detailing in json object values which can be used in
log tracking.

More detailed logging change:
https://gist.github.com/riyadixitagra/c251685c1ba84248181891f7bc282395

Tested:
Ran a power off, on, cycle, and reset-reload.

Change-Id: I0485035f15f278c3fd172f0581b053c1c37f3a5b
Signed-off-by: Riya Dixit <riyadixitagra@gmail.com>
diff --git a/subprojects/phosphor-logging.wrap b/subprojects/phosphor-logging.wrap
new file mode 100644
index 0000000..71eee8b
--- /dev/null
+++ b/subprojects/phosphor-logging.wrap
@@ -0,0 +1,6 @@
+[wrap-git]
+url = https://github.com/openbmc/phosphor-logging.git
+revision = HEAD
+
+[provide]
+phosphor-logging = phosphor_logging_dep