Define explicit ownership for custom appenders and formatters

Add SharedLogState for synchronized value data and factories for
independently owned appender state and captured formatter closures.
Reject unsafe configuration state, update the test collector to value
snapshots, and document the breaking APIs in version 3.0.0.

Expand ORC ownership and sanitizer coverage and reject stale test
executables.

tests/regressions.nim

@@ -1,5 +1,6 @@
 import std/[os, osproc, strutils, tempfiles, unittest]
 import ../src/namespaced_logging
+import ./ownership
 
 type
   CloneControl = object
@@ -16,18 +17,19 @@ method clone(app: FallibleAppender): LogAppender {.gcsafe.} =
 type
   LifetimeProbeObj = object
     destroyed: ptr int
-  LifetimeProbe = ref LifetimeProbeObj
+  LifetimeProbe = SharedLogState[LifetimeProbeObj]
 
 proc `=destroy`(probe: LifetimeProbeObj) =
-  inc probe.destroyed[]
+  if probe.destroyed != nil:
+    inc probe.destroyed[]
 
-proc ignoreMessage(state: LifetimeProbe, msg: LogMessage) {.gcsafe, noconv.} =
+proc ignoreMessage(state: var LifetimeProbe, msg: LogMessage) {.gcsafe, noconv.} =
   discard
 
 proc watchedService(destroyed: ptr int): LogService =
   result = initLogService()
   result.addAppender(initCustomLogAppender(
-    LifetimeProbe(destroyed: destroyed), ignoreMessage))
+    initSharedLogState(LifetimeProbeObj(destroyed: destroyed)), ignoreMessage))
 
 proc createAndReleaseService(destroyed: ptr int) =
   var service = watchedService(destroyed)