info: show Linux formulae details and analytics

- This makes use of the new /api/formula-linux and /api/analytics-linux
  endpoints in formulae.brew.sh to give Linux users up to date formula and
  analytics info for their installed core formulae.

Before, on Linux, the macOS stats for the `ack` formula:

```
$ brew info ack
[...]
==> Analytics
install: 12,422 (30 days), 32,742 (90 days), 97,788 (365 days)
install_on_request: 10,778 (30 days), 28,339 (90 days), 85,202 (365 days)
build_error: 0 (30 days)
```

Now, on Linux, the Linux stats for the `ack` formula:

```
$ brew info ack
[...]
==> Analytics
install: 95 (30 days), 242 (90 days), 737 (365 days)
install_on_request: 94 (30 days), 241 (90 days), 734 (365 days)
build_error: 0 (30 days)
```