Update meson and subprojects

Few changes related to meson:
- GTest and boost were updated.
- Boost is now built locally in case it is not installed on system.
- Minor meson.build refactor.

Testing done:
- local build is working fine, when subprojects are not installed on the
  system,
- local build is working fine, when subprojects are installed on the
  system,
- yocto build is working fine.

Signed-off-by: Szymon Dompke <szymon.dompke@intel.com>
Change-Id: Ib62092946d6ffafb1884d1ba3eab97bed243dd12
diff --git a/subprojects/boost.wrap b/subprojects/boost.wrap
new file mode 100644
index 0000000..b10bf3d
--- /dev/null
+++ b/subprojects/boost.wrap
@@ -0,0 +1,10 @@
+[wrap-file]
+source_url = https://boostorg.jfrog.io/artifactory/main/release/1.80.0/source/boost_1_80_0.tar.bz2
+source_hash = 1e19565d82e43bc59209a168f5ac899d3ba471d55c7610c677d4ccf2c9c500c0
+source_filename = boost_1_80_0.tar.bz2
+
+directory = boost_1_80_0
+patch_directory = boost
+
+[provide]
+boost = boost_dep