Support arbitrary grouping of viruses for strategic reasons

[renatomassaro]

Give players the option to group viruses (and Database entries) as they want, so different strategies may be applied.

Examples:

• I want to use bounce 1 when collecting money from viruses belonging to group "Noobs".
• I want to collect money only from viruses belonging to group "TOP". Collect every hour because they may disappear soon. Use bounce 2 for extra protection.
• I want to launch a DDoS attack with botnet A. Counter-attacks will use botnet B.

[renatomassaro]

Bounce grouping added at #378