Update `profsea-climate` baseline period

Currently the baseline period for projections is 1986-2005, as per AR5. This should probably at least be updated to the AR6 baseline period (1996-2014).

A change could also be made to make baseline changes more straight forward, so a user could specific the baseline they want to run with themselves.

Start by locating where the profsea-climate baseline period is defined and how projection settings are passed through the tool. Confirm how the current 1986-2005 period is used, then determine what is needed for the AR6 1996-2014 period or a user-selected baseline. Done means the selected baseline is applied consistently to projections.

Written by the indexing model from the issue text.