Generate a coverage report for End to end tests (#5667)

* Generate coverage report after running tests

* Wait for integration program to stop/start

variants/portduino/platformio.ini

@@ -9,3 +9,7 @@ build_flags = ${portduino_base.build_flags} -O0 -I variants/portduino
 board = cross_platform
 lib_deps = ${portduino_base.lib_deps}
 build_src_filter = ${portduino_base.build_src_filter}
+
+[env:coverage]
+extends = env:native
+build_flags = -lgcov --coverage -fprofile-abs-path ${env:native.build_flags}