refactor: make lokinet-bootstrap a native executable

* pull in cpr
* tidy up windows.sh
* rename main.cpp to lokinet.cpp to satisfy my autism
* add llarp::GetDefaultBootstrap()

.gitmodules

@@ -35,3 +35,6 @@
 [submodule "external/ngtcp2"]
 	path = external/ngtcp2
 	url = https://github.com/ngtcp2/ngtcp2.git
+[submodule "external/cpr"]
+	path = external/cpr
+	url = https://github.com/whoshuu/cpr

contrib/windows.sh

@@ -3,7 +3,6 @@ set -e
 set +x
 mkdir -p build-windows
 cd build-windows
-# build it
 cmake \
       -G Ninja \
       -DCMAKE_EXE_LINKER_FLAGS=-fstack-protector \

external/CMakeLists.txt

@@ -25,6 +25,7 @@ if(SUBMODULE_CHECK)
     check_submodule(uvw)
     check_submodule(cpr)
     check_submodule(ngtcp2)
+    check_submodule(cpr)
   endif()
 endif()
 
@@ -83,3 +84,6 @@ set(ENABLE_BORINGSSL OFF CACHE BOOL "Disable boringssl for ngtcp2")
 
 add_definitions(-D_GNU_SOURCE)
 add_subdirectory(ngtcp2 EXCLUDE_FROM_ALL)
+
+set(CPR_BUILD_TESTS OFF)
+add_subdirectory(cpr)