CDFs graphs for Exits and Guard+Exits, for simulated and live Tor network

We will need the following graphs:

    - CDFs for Exits and Guard+Exits
      - 'exit-kibibytes-read'+'exit-kibibytes-written'/'epoll_cnt' 
      - 'exit-kibibytes-read'+'exit-kibibytes-written'/'epoll_wait'

We can get this info from descriptor and shadow logs.

Furthermore we will also need the following graphs:

  - Graphs:
    - Utilization CDFs: graph for all relays, and one graph each for "Guard",
      "Exit", "Middle", "Guard+Exit"
      - take the bandwidth history from extra-info, and divide it by the advertized
        bandwidth from the descriptor.
        - In Shadow, we may have to use the Link capacity instead of adv bw,
          if clients don't burst enough in 1 sim period to get adv bw high
          enough

We also want a new baseline date range, for a flooding period.

For more details and prioritization, see tpo/network-health/metrics/analysis#40008 (comment 2764299)

cc\ @mikeperry cc\ @jnewsome