RuleCache: reorganize to keep group structure

RuleCache: reorganize to keep group structure

Currently we 'or' combine all objects of a type (from/to/what/when)
regardless of group, so we only keep a single list of all objects.

Since we want to introduce different logic (and/invert) we want to keep
the configured group structure. This patch does this, without changing
the current matching logic (still all 'or'-ed).

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
[S.I.: fix 2 typos in commit-message]
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>