Add configurations: email per site and timeout.

[busykoala]

We will need configurations to set following parameters:

• Timeout time for fetching external links
• Email addresses for report receivers (needs to be set for each PloneSite)

Ideas to solve:

• Config file
• Argument added to run command (usually in cronjob setup)

[busykoala]

@maethu what solution would you suggest here?

[busykoala]

Solved in #42