export detectors and standalone detect/collect functions

[Le0Developer]

We're trying to implement botd by using collect() client-side, sending the components to the server and then running detect() there.
The current BotDetector class interface does not allow that kind of use.

My suggestion: move detect and collect into standalone functions that are exported.
The BotDetector class could use those functions itself too, to prevent code duplication. (this would also allow tree-shaking to remove the BotDetector class or detectors - assuming they are marked as pure)

The client-side is possible to implement manually (by copying the function out of the class and adapting it), because luckily the sources list is exported.
The server-side validation is impossible because detectors is not currently being exported.

[xnerhu]

Released in v1.7.0