Add page for past execs and internal members #370

We would like to have a page showcasing previous terms' execs and internal committee members (programme committee + systems committee + website committee). This will help preserve a strong connection between current and former execs.

Some ideas:

Include only names to begin with, and perhaps add images later once we figure out how much space we have
Add collapsing, similar to the events page
Maybe have separate sections for execs and internal committee
Maybe split it by year

Here are some more specifications as to what the page should look like:

Organize the page into sections based on term, with most recent terms at the top
For each term, list the exec positions + person's name ~~+ Quest id~~
For the past 3 terms (ie. 1 year), display this information along with the exec's photo in a format similar to the committees on the Meet the Team page (https://csclub.uwaterloo.ca/about/team)
~~For older terms, have a collapsible section for each term, maybe with an option to expand all/collapse all~~ Include a link at the bottom of the page (and maybe also at the top of the page) to the Past Executive page on the CSC Wiki

As part of this ticket, we need to:

OPTIONAL: Submit a Design request, ~~mostly for some kind of collapsible list component~~ if we want to have a pretty header/graphic at the top of the page - otherwise we can just use a plain header
Decide how far back we want to go with the past execs - https://wiki.csclub.uwaterloo.ca/Past_Executive has some interesting historical information, but we need to decide how much we want to include on the website. EDIT: this is still being finalized, but for now we can just show the past 3 terms
Figure out the best way to store the data (eg. markdown, json, something else) - this decision may be influenced by our decision in the previous point
After all the above has been done, we can implement the page and any necessary components :)