Recommend that people take two consecutive weeks off each year

@BarbieGitLab mentioned in https://gitlab.com/gitlab-com/people-ops/General/issues/149#note_86556727

However, Managers should DEFINITELY be encouraging their Team Members to take time off. We all need that refresh and reboot, far more than once every 4 years.

We already have wording around this in the handbook, but if you take two weeks off in a year, spread out over 10 individual days, that's not going to be good for you. As this is only a recommendation, I'd like to be more ambitious: recommend that people take a consecutive two-week block off each year.

There is some prior art here (although the driving reason is a different one). For instance, https://www.fdic.gov/news/news/financial/1995/fil9552.html says:

The FDIC endorses the concept of a vacation policy that allows active officers and employees to be absent from their duties for an uninterrupted period of no less than two weeks. During this time, their duties and responsibilities should be assumed by other employees. This basic control has proven to be an effective internal safeguard in preventing fraud. In addition, such a policy is viewed as a benefit to the well-being of the employees and can be a valuable aid to the institution's overall training program.

We are not concerned with fraud here, but the last sentence seems very relevant.