feat: allow setting how deeply a logger should search into the stack

`logger.callStackLinesToSkip = 2` will make it skip 2 extra lines above the base.

You can't skip negative lines

Refs: #1268

lib/logger.js

@@ -94,6 +94,8 @@ class Logger {
     this.category = name;
     this.context = {};
     /** @private */
+    this.callStackSkipIndex = 0;
+    /** @private */
     this.parseCallStack = defaultParseCallStack;
     debug(`Logger created (${this.category}, ${this.level})`);
   }
@@ -120,6 +122,20 @@ class Logger {
     categories.setEnableCallStackForCategory(this.category, bool === true);
   }
 
+  get callStackLinesToSkip() {
+    return this.callStackSkipIndex;
+  }
+
+  set callStackLinesToSkip(number) {
+    if (typeof number !== 'number') {
+      throw new TypeError('Must be a number');
+    }
+    if (number < 0) {
+      throw new RangeError('Must be >= 0');
+    }
+    this.callStackSkipIndex = number;
+  }
+
   log(level, ...args) {
     const logLevel = levels.getLevel(level);
     if (!logLevel) {
@@ -150,7 +166,10 @@ class Logger {
     if (this.useCallStack) {
       try {
         if (data[0] instanceof Error) {
-          callStack = this.parseCallStack(data[0], baseCallStackSkip);
+          callStack = this.parseCallStack(
+            data[0],
+            this.callStackSkipIndex + baseCallStackSkip
+          );
         }
       } catch (_err) {
         // Ignore Error
@@ -159,7 +178,9 @@ class Logger {
         callStack ||
         this.parseCallStack(
           new Error(),
-          defaultErrorCallStackSkip + baseCallStackSkip
+          this.callStackSkipIndex +
+            defaultErrorCallStackSkip +
+            baseCallStackSkip
         );
     }
     const loggingEvent = new LoggingEvent(