move-onlyish: Move logging levels to util/log.h

This is not strictly move-only because BCLog::Level is now defined as a type
alias for util::log::Level;

Review with --color-moved=dimmed-zebra --color-moved-ws=ignore-all-space

Co-authored-by: Ryan Ofsky <ryan@ofsky.org>

src/logging.h

@@ -63,13 +63,6 @@ struct LogCategory {
 };
 
 namespace BCLog {
-    enum class Level {
-        Trace = 0, // High-volume or detailed logging for development/debugging
-        Debug,     // Reasonably noisy logging, but still usable in production
-        Info,      // Default
-        Warning,
-        Error,
-    };
     constexpr auto DEFAULT_LOG_LEVEL{Level::Debug};
     constexpr size_t DEFAULT_MAX_LOG_BUFFER{1'000'000}; // buffer up to 1MB of log data prior to StartLogging
     constexpr uint64_t RATELIMIT_MAX_BYTES{1024 * 1024}; // maximum number of bytes per source location that can be logged within the RATELIMIT_WINDOW

src/util/log.h

@@ -29,4 +29,18 @@ private:
     std::source_location m_loc;
 };
 
+namespace util::log {
+enum class Level {
+    Trace = 0, // High-volume or detailed logging for development/debugging
+    Debug,     // Reasonably noisy logging, but still usable in production
+    Info,      // Default
+    Warning,
+    Error,
+};
+} // namespace util::log
+
+namespace BCLog {
+//! Alias for compatibility. Prefer util::log::Level over BCLog::Level in new code.
+using Level = util::log::Level;
+} // namespace BCLog
 #endif // BITCOIN_UTIL_LOG_H