The test failure was due to pollBorker waiting the full 5 seconds before
polling for the first time.

The lint errors were some trailing whitespace and unecessary fat arrows

This enables breaking the loop from the outside and cleans up the
countdown

This doesn't apply to the webextension but hasn't been factored out in
the build step yet.

Updated the tests to pass with our new snowflake-ips-total stat

Added another metrics item that counts the total availabel snowflakes
(unique by IP address)

- removed trailing ","s
- removed unecessary space before seconds

Also moved the geoip check to occur after we've make sure the proxy IP
hasn't yet been recorded. This is will cut down on unecessary
computation.

Added unit tests for metrics logging. Refactored the logMetrics()
function to allow for easier testing

Change it so that we log the geoip country code of proxies if they poll
within the current metrics epoch. We make sure we log by unique IP
address

Output is now printed out in Tor Directory Protocol Format, as specified
in https://trac.torproject.org/projects/tor/ticket/21315#comment:19.

Added three new metrics:
- proxyIdleCount counts the number of times a proxy polls and receives
no snowflakes
- clientDeniedCount counts the number of times a client requested a
snowflake but none were available
- clientProxyMatchCount counts the number of times a client successfully
received a snowflake

Set the resolution of metrics data collection to be every 24 hours

So far, we request a certificate each time we start the broker.  Let's
Encrypt maintains several rate limiters and if we exceed one of them, we
won't get a certificate.  Worse, since we don't store certificates, we
won't even be able to use an old one.

This patch uses autocert's DirCache structure to cache certificates on
disk.

This patch fixes <https://bugs.torproject.org/30512>.

MaxBytesReader is only documented for server side reads, so we're using
a local limitedRead function instead that uses an io.LimitedReader.

Declared limits in a commented constant

This is a fix for #26348

Amounts to the same thing as currently implemented in go-webrtc

Similar to c28c8ca4 for proxy-goc

NewBrokerContext now requires a logger so give it one to discard the
logs.

Now that the page is no longer necessary.