Establish actually good good first issues

[ChristophWurst]

Description

Going through labels recently we found the tickets tagged as good first issue. While we support the incentive behind this, in reality the tag was put on arbitrary tickets that don't qualify. A good first issue should have clear instructions of what needs to be done. Links to some good relevant documentation will be helpful. There is possible more to document.

Since these tickets mean effort, it's likely better to have fewer of them but with a higher quality than too many. Too many tickets also makes it potentially harder for new comers to pick a task.

Based on the discussion with @miaulalala and @tcitworld I would suggest we start with three tickets per repo with that label. Moreover we should define a process of regularly checking if enough tickets are there for each repo and if not promote a new lower effort ticket to a good first issue.

Affected components

I'd say all but we can also limit to apps.

• Calendar
• Calendar Resource Management
• Contacts
• Contacts Interaction
• Mail
• @nextcloud/calendar-availability-vue
• @nextcloud/calendar-js
• @nextcloud/cdav-library

To do

• Define what a good first issue should contain
• Find suitable tickets
• Tag them, untag any others
• Update their description
• Write down this process
• Possibly link to the tickets from this repo's readme