Support to load the script using an external file also

JoshaHubbers → made their first commit to this issue’s fork.

This is work in progress. Done so far:
* add config forms
* rewrite some logic and cleanup code

Todo:
* create the output
* update config-schema
* add tests

This ticket should be checked along with 📌 Move JS snippets to separate script files Active because they are doing a bit similar things.

This issue has not been updated in two years. The initial problem motivation does not tell in detail what is the added benefit of this feature and what are the uses cases.

Also we would need to check if Piwik PRO currently still supports this and if there are any security implications here. Could someone for example inject a malicious script to the site.

I think this should be closed in favour of the other ticket. The idea was that you could use your own local scripts if you would like that (I think ;-) ).

Excellent. Thank you. Closing this then.