Recognize and signal idleness

[josephbirkner]

Ravestate context should recognize whenever it encounters indecision/uncertainty/inactivity (:thinking: / :sleepy:). This is useful for the following use-cases:

1. Indecision when waiting for a missing signal to activate a high-specificity state ↪️ Fillers
2. Indecision when no activation pressure is present at all ↪️ Active engagement (Fillers, Personal QA, Games) -> Roboy is not waiting for user input.

Both situations may be modeled as functions of two new core variables:

1. :pressure: A flag which indicates, whether or not activation pressure is present at all; i.e. whether a partially fulfilled high-specificity state is blocking a fulfilled low-specificity one.
2. :activity: A counter for the number of states that are currently partially fulfilled.

For example:

• Fillers may be adequate, when :pressure has been true for some minimum time (Filler to bridge "awkward" waiting)
• Active engagement may be adequate, when :activity has dropped to zero.

Note, that :pressure is true -> :activity > 0, but not :activity > 0 -> :pressure is true: Multiple partially fulfilled states may be present, without a fulfilled one generating activation pressure.

Therefore, two idle signals will be realized in an idle module:

1. idle:impatient ↪️ Fillers
2. idle:bored ↪️ Active engagement (Fillers, Personal QA, Games)