re-organizing EVERYTHING

Re-organized whole site, created header and footer files that are
included on all pages (since we are using PHP after all). Moved all old
files into “legacy folder” (delete everything we don’t need from there
whenever you’d like).
Also more style updates: updating breakpoint for navbar collapse so it
doesn’t look weird, also adjusted margins for small screens so “beta”
doesn’t force nav toggle button above, and other tweaks here and there.