Add project specific stopwords to StopWord list

[jmichelberger]

Is your feature request related to a problem? Please describe.
The stopword list is currently a static list in the tweetwall core. If there are additional stopwords necessary to be added to the stopword list it is currently only possible by a resource file modification to the core. These stopword list shoult be extendable by a configuration in the jsonn of the dedicated event project.

Describe the solution you'd like
Add a section to the json config to extend the list.

[jmichelberger]

I think we need something like 
- exact outlist
- regex outlist containing line matchers per config line. See https://discourse.pi-hole.net/t/load-regexps-from-host-file/25829
- exact inlist
- regex inlist containing line matchers per config line.
matches in blacklist should filtered out, but if in whitelist remain in.

Lists could be loaded via same mechanism as the static stoplist is loaded.

It should be possible to have comments lines starting with #.

[jmichelberger]

It could be extended by storing the lists at GitHub and the Stoplist checks every minute if there is a new version of the list files are available. In that case the new files could be downloaded and the runtime lists can be refreshed.