Shift to boost asio library

This commit shifts vpd manager from sdbusplus event loop to
boost io_context event loop.
The shift was done to have a more flexible way to perform
async Dbus calls.
For example read/write of vpd data can be performed
asynchronously.

It also removes dependency of Manager class on the interface
class created as a part of Phosphor-Dbus-Interface repo.

Test:
- Introspect com.ibm.VPD.Manager /com/ibm/VPD/Manager to ensure
that all the methods exposed under com.ibm.VPD.Manager interface
matches to the ones documented under PDI repo.

- Make DBus call to each of the exposed api to ensure that the
funcation calls are working fine.

-To ensure bios handler call back is working.
Stop vpd-manager service.
Stop pldm service.
Start vpd-manager service
Start pldm service.
Should recieve callback.

-To ensure gpio call back
std::cout were added to callback function being trigerred on
timer expiration and the same were verified in journal.

Signed-off-by: Sunny Srivastava <sunnsr25@in.ibm.com>
Change-Id: I00640f64de487d5244e8be2e7a3f3d63a013644e
diff --git a/vpd-manager/bios_handler.cpp b/vpd-manager/bios_handler.cpp
index 4271665..d4a5330 100644
--- a/vpd-manager/bios_handler.cpp
+++ b/vpd-manager/bios_handler.cpp
@@ -29,7 +29,7 @@
     // the signal handler, call restoreBIOSAttribs
     static std::shared_ptr<sdbusplus::bus::match_t> nameOwnerMatch =
         std::make_shared<sdbusplus::bus::match_t>(
-            bus,
+            *conn,
             sdbusplus::bus::match::rules::nameOwnerChanged(
                 "xyz.openbmc_project.PLDM"),
             [this](sdbusplus::message_t& msg) {
@@ -86,7 +86,7 @@
 {
     static std::shared_ptr<sdbusplus::bus::match_t> biosMatcher =
         std::make_shared<sdbusplus::bus::match_t>(
-            bus,
+            *conn,
             sdbusplus::bus::match::rules::propertiesChanged(
                 "/xyz/openbmc_project/bios_config/manager",
                 "xyz.openbmc_project.BIOSConfig.Manager"),