Channel world map improvements

[nymkappa]

• [x] When the zoom level is high, draw nodes on top of channels and the circle bigger so it's easier to click on it https://github.com/mempool/mempool/pull/2274
• [ ] Show node summary in tooltip (capacity, channels, geolocation info)
• [ ] Experiment with channels tooltip (it may spam too much but need to try)
• [X] Make channel opacity dynamic based on the channel count so it's not too bright/saturated
  • Hardcoded a limit of 10,000 biggest channels to display
• [ ] Scale node dots based on their liquidity