Download (clone) statistics
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For open source projects it is helpful to have download statistics to gauge project popularity. We should add basic download statistics.
<details><summary>Original request</summary>
For an open source project, it is important to have access to download statistics.
It seems that this feature is not available in gitlab (it is possible with github)
That is very strange. Is there a reason for this ?
Are there plans to add this feature ?
</details>
## Proposal
- Add chart showing the number of daily cloners for the last two weeks or 30 days
- Add chart showing the number of unique daily cloners (based on user id, falling back to IP address) for the last two weeks or 30 days
- Add Traffic API resource to retrieve clone statistics
```
{
"count": 100,
"uniques": 50,
"clones": [
{
"timestamp": "2018-01-10T00:00:00Z",
"count": 10,
"uniques": 5
},
...
]
}
```
### Mockup
Add new area in "[Repository analytics](https://gitlab.com/gitlab-org/gitlab/-/graphs/master/charts)" (Analyze > Repository analytics) called `Download statistics`.
- Dropdown to select between `Last 14 days` and `Last 30 days`
- The [segmented control](https://design.gitlab.com/components/segmented-control) is being depreciated.
- Display the date range of the selected dropdown option.
- Use single stat blocks for `Total downloads` and `Unique downloads`
- The purpose is to sum up all of the daily downloads over the selected time period as an overview.
- Line chart to show total and unique daily downloads over the time period
- Ensure that a legend is present
- On hover, should display `date`, `total daily download count`, and `unique daily download count`.

## Future
A future improvement would be to track download statistics of binaries attached to releases
## Outcome of spike
Find out if data already exists in gitaly and how to expose it for the frontend to consume
https://gitlab.com/gitlab-org/gitlab/-/issues/15807#note_1447246723
See comment https://gitlab.com/gitlab-org/gitlab/-/issues/15807#note_1515798811
issue