Set report frequency

[tomaskulich]

Each project should have a frequency attribute. If a new report is missing for more than frequency days, in the left bar:

• put the project to the top
• write project name in red

Frequency should be set by posting a slack message (the mechanism similar to archiving the projects) of a form (frequency :__prj1 freq1 :__prj2 freq2 ...)

The default frequency for a new project is16 days.