Improve error / console handling / output

[fako1024]

Right now error (and informational) logging to the console is a bit flaky. There's a few things to consider IMHO:

• Formatting: There's a few places where we differentiate between pretty-printing and non-pretty-printing, which is nice, but there's at least one place in root.go of goQuery where we "force" pretty printing although we don't know if it's properly supported (plus, the way it's done feels a bit clumsy):

	if err != nil {
		return fmt.Errorf(`failed to execute query

      Error: %w
  Statement:
%s`, err, types.PrettyIndent(stmt, 4))
	}

• Logging: It seems that logging is not fully set up as intended, there is an informational line in DBWorkManager.go that should trigger on cancellation, but doesn't (or at least it's not shown):

// query was cancelled, exit
logger.Infof("Query cancelled (workload %d / %d)...", w.nWorkloadsProcessed.Load(), w.nWorkloads)

• Case: I'm pretty sure there are still some log lines which use uppercase at the beginning of the line (while for errors and most informational output we use lowercase). Might make sense to review it all at once.
• Fix the indentation on the condition parsing

There may be more issues, but I think some form of refactoring (in particular adding a few helpers to make stuff easier) would help.

[els0r]

Something noticed when the infinite recursion error was fixed: now, the condition parsing error isn't aligned in a user-friendly way. As in: the cursor doesn't help anymore:

Error running query: failed to prepare query:

  Field:   condition
  Message: invalid condition
  Details: host 1.2.3.4
     ^
expected comparison operator

Should be:

Error running query: failed to prepare query:

  Field:   condition
  Message: invalid condition
  Details: 

   host 1.2.3.4
       ^
expected comparison operator

[els0r]

Logging: It seems that logging is not fully set up as intended, there is an informational line in DBWorkManager.go that should trigger on cancellation, but doesn't (or at least it's not shown)

The default level is Warn, hence you don't see the info messages.