chore(streamer): remove vendored cvmmap client

.gitmodules

@@ -1,6 +1,3 @@
-[submodule "lib/cvmmap-client-cpp"]
-	path = lib/cvmmap-client-cpp
-	url = https://github.com/crosstyan/cvmmap-cpp-client
 [submodule "lib/CLI11"]
 	path = lib/CLI11
 	url = https://github.com/CLIUtils/CLI11

src/core/frame_source.cpp

@@ -93,11 +93,11 @@ public:
 			client_ = std::move(client);
 		} catch (const std::exception &e) {
 			prepared_.store(false, std::memory_order_release);
-			return std::unexpected(std::string("cvmmap-client-cpp init failed: ") + e.what());
+			return std::unexpected(std::string("cvmmap-core client init failed: ") + e.what());
 		}
 
 		spdlog::info(
-			"real source backend initialized via cvmmap-client-cpp: target='{}'",
+			"real source backend initialized via cvmmap-core client: target='{}'",
 			client_target_);
 		return {};
 	}