Add Auto-switching of Activity by Conditions

[ramack]

Add conditions to sort activities and switch the active activity automatically. For auto switching, conditions shall be be selectable manually as required conditions or "probable" conditions. -->> Remark: do we really need that?

• [x] predecessor activity active (this alone shall never reach the threshold for auto-switching, for sure)
• [ ] resume last activity (e. g. "Short Break" will very likely just interrupt the previous activity which is restarted afterwards)
• [ ] datetime modulo conditions
  • [x] Time of day
    • [ ] modulo behavior
    • [ ] real cyclic update, add new Service like RefreshService
  • [ ] weekday
  • [ ] date
• [ ] recurrence evaluation (never do autoswitching based on this)
• [ ] wifi network
• [ ] bluetooth connection
• [x] location #49
• [ ] gps speed
• [ ] movement / sensors detecting things like jogging
• [ ] illumination level
• [ ] NFC tags?
• [ ] calendar events

Due to sorting we also have a "Alphabetical"Condition, likelihood for autoswitching should not really be influenced by this, but it might be sufficient to keep the weight small for it.

It seems reasonable to require a certain "distance" of the most likely to the second activity, that only if one is outstanding more likely it is auto selected. This distance will solve the sort-only conditions like alphabetical.

do not forget to adjust the wiki after implementing this.

• [ ] add new notification and a channel to show that an activity changed. Prio shall by HIGH, beep and vibrate as default. Show there the new selected activity and the actions "CHANGE", "DELAY" and "OK"

[ramack]

also important might be even the case, that no new activity was reliably detected, but still the current activities likelihood to stay active reduced below the threshold. In that case a notification shall popup to ask whether it is intended to do that for so extraordinary long time, at this unusual place or whatever condition might have decreased.

[ramack]

linked to #182