### Summary
Tracking issue: https://github.com/wormhole-foundation/wormhole-explorer/issues/276
This pull request implements the endpoint `GET /api/v1/top-assets-by-volume`, which returns the assets that have the highest volume. Internally, the endpoint uses data summarized daily to speed up query execution times.
This endpoint has a mandatory query parameter named `timerange`, which must be set to `7d`, `15d` or `30d`.
### Summary
This pull request adds volume metrics to influxdb. Also, it adds the 24h volume metric to `GET /api/v1/scorecards`.
Tracking issues: https://github.com/wormhole-foundation/wormhole-explorer/issues/221, https://github.com/wormhole-foundation/wormhole-explorer/issues/280
### Changes:
* The `parser` service no longer generates metrics for influxdb. All metrics-related code was removed from that service, that code was moved to the analytics service instead.
* New volume metrics were added to the analytics service.
* The notional cache was modified to use token names (i.e.: ticker symbols) as keys instead of chain IDs.
* The notional cache reader was moved to the `common/client/cache` package.
* A little bit of duplicated code between the cache reader and writer was removed.
* A 24h volume metric was added to `GET /api/v1/scorecards`.
* A dictionary that stores token metadata was added under `common/domain/tokenbridge.go`. More tokens will be added to it in the near future.
### Summary
This pull request adds the `GET /api/v1/scorecards` endpoint, which is required by the wormscan frontend.
Most of the fields that this endpoint should return are being omitted because the data is not currently available on the backend. Those fields will be added iteratively as the data becomes available.
The current format of the response is:
```json
{
"total_tx_count": "1300200",
"24h_tx_count": "4200"
}
```
Tracking issue: https://github.com/wormhole-foundation/wormhole-explorer/issues/221
## Deployment details
In order to populate the `"total_tx_count"` metric, a task is needed in influxdb:
```
$ cat total-vaa-count.flux
option task = {
name: "Total number of emitted VAAs",
every: 1m
}
from(bucket: "wormhole-explorer")
|> range(start: 2018-01-01T00:00:00Z)
|> filter(fn: (r) => r._measurement == "vaa_count")
|> group(columns: ["_measurement"])
|> set(key: "_measurement", value: "total_vaa_count")
|> count()
|> map(fn: (r) => ({r with _time: now()}))
|> map(fn: (r) => ({r with _field: "total_vaa_count"}))
|> to(bucket: "wormhole-explorer", org: "xlabs")
```