Manage impulse notes

An impulse note is a record about a single observation in the personal development. This feature should be reachable (at least) from the personal overview in #5 (closed).

Everyone can create impulse notes, even about themselves.

Apart from that, the following operations require some permissions:

• View impulse notes: Members of the "responsible group" of the linked category, "responsible person", and "about person"
• Delete impulse notes: Members of the "responsible group" of the linked category
• Edit impulse notes: Members of the "responsible group" of the linked category