Complete the process of using myFuncName in all log messages

[atc0005]

Example:

+               myFuncName := caller.GetFuncName()

                log.Debugf(
-                       "Config file %q exists, attempting to open it",
+                       "%s: Config file %q exists, attempting to open it",
+                       myFuncName,
                        sanitizedFilePath,
                )
                // use direct function call here instead of our variable to comply
                // with gosec linting rules
                fh, err := os.Open(filepath.Clean(config.ConfigFile()))
                if err != nil {
-                       return nil, fmt.Errorf("unable to open config file: %v", err)
+                       return nil, fmt.Errorf(
+                               "%s: unable to open config file: %v",
+                               myFuncName,
+                               err,
+                       )

The exception might be where including the function name adds visual noise for output meant to be directly read/acted upon. That said, our target audience is a sysadmin who should be familiar with (or at least appreciate) the verbose nature of the log/error messages.

I've been making these changes as I've resolved recent linting issues (and likely before that), but spinning this issue off as a reminder to continue the work going forward.

[atc0005]

See also GH-119 and f2aafe9 specifically.