cockroachdb: support all v23.2 metrics

CockroachDB exposes its metrics via a
[Prometheus endpoint](https://www.cockroachlabs.com/docs/v23.2/monitoring-and-alerting#prometheus-endpoint)
on `/_status/vars`. In CockroachDB v23.2 there are
[~1500 metrics exposed](https://github.com/cockroachdb/cockroach/blob/f6d211271f2ba51b57d083ffc5c2cbadc38b5b23/docs/generated/metrics/metrics.html)
via this endpoint.

After deduplication and removing histogram metrics (i.e., `.bucket`,
`.sum`), the `cockroachdb` Datadog integration only supports 372 metrics
per its
[metadata.csv](https://github.com/DataDog/integrations-core/blob/2ca3e82bb56a4215860a38aa2b7707137b5240c1/cockroachdb/metadata.csv)
file.

This patch updates the `cockroachdb` Datadog integration to support all
of the metrics exposed by CockroachDB as of the latest stable release,
which is v23.2 at the time of this writing.

Resolves #16694.

cockroachdb/changelog.d/16697.changed

@@ -0,0 +1 @@
+Support all CockroachDB v23.2 metrics.

cockroachdb/cmd/generate/README.md

@@ -0,0 +1,29 @@
+# generate
+
+A program to generate the `metadata.csv` and metric name mapping required by the
+`cockroachdb` Datadog integration.
+
+## Usage
+
+Build the `generate` program.
+
+```
+go build .
+```
+
+Download the `metrics.html` from
+https://github.com/cockroachdb/cockroach/blob/master/docs/generated/metrics/metrics.html.
+
+Run the generator against the `metrics.html` file.
+
+```
+generate metrics.html
+```
+
+Afterwards, you'll have a `metadata.csv` and `mapping.txt` file in your current
+working directory.
+
+Replace `cockroachdb/metadata.csv` with the generated `metadata.csv` file.
+
+Update the `METRIC_MAP` in `cockroachdb/datadog_checks/cockroachdb/metrics.py`
+with the content from `mapping.txt`.

cockroachdb/cmd/generate/go.mod

@@ -0,0 +1,11 @@
+module generate
+
+go 1.22.1
+
+require github.com/mdigger/htmlx v1.0.1
+
+require (
+	github.com/mdigger/wstat v0.0.0-20210601091130-720a00d2ac3a // indirect
+	golang.org/x/net v0.0.0-20210614182718-04defd469f4e // indirect
+	golang.org/x/text v0.3.6 // indirect
+)

cockroachdb/cmd/generate/go.sum

@@ -0,0 +1,13 @@
+github.com/mdigger/htmlx v1.0.1 h1:kRQkxy47ZMpLQDJvla0UuklO8dq03gaHAYVngUyxUB8=
+github.com/mdigger/htmlx v1.0.1/go.mod h1:wvTL2EPWXHGVyER1/2wbjI04yBOIHuseQyZ7lYK1UXA=
+github.com/mdigger/wstat v0.0.0-20210601091130-720a00d2ac3a h1:+ysqmGWt5uyXiXF8v8dvogWreUS4cuLRNexgZJSc7E4=
+github.com/mdigger/wstat v0.0.0-20210601091130-720a00d2ac3a/go.mod h1:HakDzzxSevC21s4FVwJmfpV4Xm4IiRR8Y7/ly73h7NU=
+golang.org/x/net v0.0.0-20210525063256-abc453219eb5/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/net v0.0.0-20210614182718-04defd469f4e h1:XpT3nA5TvE525Ne3hInMh6+GETgn27Zfm9dxsThnX2Q=
+golang.org/x/net v0.0.0-20210614182718-04defd469f4e/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.6 h1:aRYxNxv6iGQlyVaZmk6ZgYEDa+Jg18DxebPSrd6bg1M=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=