[pkg/ottl] Adapt time parsing error messages to include the ctime directives

[bacherfl]

Description

This PR adapts the Time function to check for time.ParseError errors. If such an error is received by the function, it wraps it into a custom error type in order to include the provided ctime layout string instead of the go-native layout string.

Link to tracking issue

Fixes #35176

Testing

Adapted the unit tests of the Time() function

[edmocosta]

I'm thinking about ways of not having this logic/substitutes replicated here, and I think we could maybe achieve that by adding a new function into the ctimefmt package that takes a ctime-like format and returns a map from the Go's native elements to theirs c-time substitutes, something like:

func GetNativeSubstitutes(format string) map[string]string {
	nativeDirectives := map[string]string{}
	directives := ctimeRegexp.FindAllString(format, -1)
	for _, directive := range directives {
		if val, ok := ctimeSubstitutes[directive]; ok {
			nativeDirectives[val] = directive
		}
	}
	return nativeDirectives
}

With that method, we could then create the lookup map outside of the returned function (once), and just do the lookup whenever the parsing error happens. It wouldn't be necessary to handle duplicate directives as well, as the function would only return the used native elements. WDYT?

[edmocosta]

I think it would be safer to not modify the time.ParseError fields. We could maybe have a custom wrapper instead, that mimics the time.ParseError.Error() behavior but using the directives.