Dashboard cache session info

[Casper-Guo]

Most of the delay in the dashboard originates from the need to ping F1 and Ergast API to request session name and driver list

These requests are not evenly distributed amongst all races. More recent races will have more hits.

It makes sense to cache the result of these requests. Will need to modify get_session_info to return immutable types

Pros:

• Reduce waiting in the dashboard
• Future proof against fastf1 rate limit

Cons

• Might persist incorrect results, for example when Ergast is down temporarily