Document steps to run the donation campaign

For this year, we should document how to run the donation campaign, so that other people than us could do it.

- define a theme & an objective

- define dates

- write blog posts (how, how many?)

- tweet

- how to use anchors for stats

- how to analyze the stats
- etc.

team: u, sajolida

Parent Task: #14877 (closed)

Related issues

• Related to #12693
• Blocked by #15881 (closed)

Original created by @u on 15346 (Redmine)