[Runtime] Move EMPER_* environment variable handling into module

Also add a DBG message that is emitted if such a EMPER_* environment variable has been processed.

emper/lib/env.hpp

@@ -9,8 +9,7 @@
 
 namespace emper::lib::env {
 
-static auto getBoolFromEnv(const std::string&& key) -> std::optional<bool> {
-	DBG("parse " << key << " environment variable");
+static auto getBoolFromEnv(const std::string& key) -> std::optional<bool> {
 	char* envVar = std::getenv(key.c_str());
 	if (!envVar) {
 		return std::nullopt;
@@ -29,8 +28,7 @@ static auto getBoolFromEnv(const std::string&& key) -> std::optional<bool> {
 }
 
 template <typename unsigned_type>
-static auto getUnsignedFromEnv(const std::string&& key) -> std::optional<unsigned_type> {
-	DBG("parse " << key << " environment variable");
+static auto getUnsignedFromEnv(const std::string& key) -> std::optional<unsigned_type> {
 	char* envVar = std::getenv(key.c_str());
 	if (!envVar) {
 		return std::nullopt;