Update kubernetes link to use the new github org

The old one redirects, but better to be up to date I think.

Revert "Added docs for toLower and toUpper formatting"

Added docs for toLower and toUpper formatting

Point users to Matrix/Vector bridge for IRC access

Update ruby support for histograms

Add Julius to commercial support section

At least for the moment...

Unit examples should be seconds

Blog post: "Pull does not scale - or does it?"

Add grok_exporter

Add some CNCF branding.

Clarify DNS service discovery relationship to DNS-SD

It's a common misconception to call any DNS SRV record based discovery
approach "DNS-SD". The latter is a [ratified IETF standard][rfc6763]
which specifies a naming schema and lookup mechanism in order to provide
additional structured information. Prometheus only supports basic SRV
record lookups.

[rfc6763]: https://tools.ietf.org/html/rfc6763

Emphasize the cumulative nature of a histogram.

Link the relevant Wikipedia entry.

Add reference to PHP client library

Slightly improve wording about series cardinality

Replaces deprecated `scrape_configs` in examples

According to https://prometheus.io/docs/operating/configuration/ the `target_groups` field was replaced by `static_configs`.

Remove merge conflict leftover from k8s docs

Add 1.0 announcement news bar.

Revert this after we feel that the news is not hot anymore.