fix(notification): extract notification summary from $params

Fixes #6885
chore(js): configure package.json for simpler JS testing
fix(js): elgg.normalize_url no longer modifies urls that begin with a recognized scheme

Fixes #6000
Merge pull request #7065 from ewinslow/normalize-url-b6000

fix(js): elgg.normalize_url no longer modifies urls that begin with a recognized scheme
docs(notifications): Adds docs for  'object', 'action' and 'summary' params used by notify_user()
Merge pull request #7066 from juho-jaakkola/notification-summary

Extract summary from $params in notify_user()
feature(notifications): site_notification about an annotation can now have an URL

Fixes #7055
feature(likes): improves compatibility with notification plugins

This allows for example site_notifications about new likes to include a link to the liked entity.

Refs: #7055