meson: Use boost as a dependency

Currently boost library is found via the 'cpp.find_library' call. With
this method local build of the project requires host to have the boost
libraries installed.
Since the meson have a subproject system to download missing
dependencies, rewrite boost requirement to a 'dependency' object. This
way it would be possible to build the project locally on the system
without the boost library installed.

Tested:
Both local meson build and Yocto build are performed successfully.

Change-Id: I082aeb1d6c09627ea53f58cb6cd375f080401d57
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
diff --git a/test/meson.build b/test/meson.build
index c8918f9..b2b9929 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -58,7 +58,7 @@
     include_directories: root_inc,
     build_by_default: false,
     implicit_include_directories: false,
-    dependencies: [boost_coroutine, phosphor_logging_dep, crypto, systemd, sdbusplus_dep, gtest, gmock]
+    dependencies: [boost, phosphor_logging_dep, crypto, systemd, sdbusplus_dep, gtest, gmock]
   ))
 
 # Build/add closesession_unittest to test suite