Update docs structure (#4383)

Author: andreyaksenov

Diff for: .gitignore

@@ -76,6 +76,6 @@ locale/*
 
 # tntcxx submodule
 
-/doc/how-to/getting_started_cxx.rst
-/doc/how-to/_includes
-/doc/book/connectors/cxx/
+/doc/getting_started_cxx.rst
+/doc/_includes
+/doc/connector/cxx/

Diff for: build_submodules.sh

@@ -28,12 +28,13 @@ mv -fv "${luatest_dest}/index.rst" "${luatest_dest}/_includes/"
 
 # Tarantool C++ connector
 tntcxx_root="${project_root}/modules/tntcxx"
-tntcxx_howto_dest="${project_root}/doc/how-to"
-tntcxx_api_dest="${project_root}/doc/book/connectors"
+tntcxx_howto_dest="${project_root}/doc/connector"
+tntcxx_api_dest="${project_root}/doc/connector"
 
 # Copy Tarantool C++ connector docs to the right places
 mkdir -p "${tntcxx_api_dest}/cxx/"
-mkdir -p "${tntcxx_howto_dest}/_includes"
-cp -rfv "${tntcxx_root}/doc/tntcxx_getting_started.rst" "${tntcxx_howto_dest}/getting_started_cxx.rst"
-cp -rfv "${tntcxx_root}/examples/" "${tntcxx_howto_dest}/_includes/examples/"
+mkdir -p "${tntcxx_howto_dest}/cxx/"
+mkdir -p "${tntcxx_howto_dest}/cxx/_includes/"
+cp -rfv "${tntcxx_root}/doc/tntcxx_getting_started.rst" "${tntcxx_howto_dest}/cxx/"
+cp -rfv "${tntcxx_root}/examples/" "${tntcxx_howto_dest}/cxx/_includes/examples/"
 cp -rfv "${tntcxx_root}/doc/tntcxx_api.rst" "${tntcxx_api_dest}/cxx/"