Add a policy on content deletion

[RamRS]

Stack Exchange has a policy on content deletion. Users should be allowed the freedom to remove their content, but this should be done in a way that does not take away from Biostars being a knowledge repository.

We might also follow a similar policy and disallow deletion of questions with upvoted/accepted answers and up-voted comments. We could be stricter and have users "request deletion" on posts that have any feedback on them while disabling that option on posts with upvoted answers.

Here's SE's policy: https://meta.stackexchange.com/a/5222/350751

Relevant part:

[ialbert]

what is the StackExchange policy on removing the content of a question - for example, if the question cannot be deleted directly because it was answered with upvotes, can the OP still edit and remove the content of the question say, replace it with [deleted]?