Working on Tickets page: Move "Ticket Baseline" section to SE responsibilities page

From @cynthia gitlab-com/www-gitlab-com!95157 (comment 761836844):

should this section be moved to the responsibilities page?

I believe most of this information is already there, which we should link to instead of duplicating

From @weimeng gitlab-com/www-gitlab-com!95157 (comment 762692114)

It appears that the "Working on Tickets" page is where the bulk of information on ticket baseline lives.

I do agree with the sentiment that performance doesn't belong on this page though, and that the SE responsibilities page is the better home for this.

The following links will also have to be updated:

• https://gitlab.com/gitlab-com/www-gitlab-com/blob/fc7111121fef6ad9961cf1c9fa44ea63d93981df/sites/handbook/source/handbook/support/support-engineer-responsibilities.html.md#L53
• https://gitlab.com/gitlab-com/www-gitlab-com/blob/ce4ad16533b150261dd696f8ba210912fc8e5cee/sites/handbook/source/handbook/support/managers/support-1-1s.html.md#L69