[docs.homepage] Minor style fixes

[docs] Adds documentation for OAuth (cloudprober#1059)

[tls] Allow setting min and max TLS version (cloudprober#968)

[build] Upgrade to Go 1.23.3 (cloudprober#944)

* Go build cache is broken in 1.23.0 as explained here.

[config] Provide a way to access config file directory in configs. (c…

…loudprober#911)

- Add `{{ configDir }}` macro that expands to the config file directory.
- This will be useful to specify file paths relative to the config file
  directory, e.g. oauth json config, certificates, script, etc.

[probes.dns] Don't reset latency on each run (cloudprober#834)

[common.file] Fix accessing files from Google Storage (cloudprober#783)

cloudprober#396 broke accessing Google Storage as path.join converts any double slash into a single slash.

[probes.external] Fix serverutils. (cloudprober#748)

We should not be writing to buffered stdout and stderr. This change
was introduced recently in v0.13.4:
  github.com/cloudprober/pull/695

[surfacers.prometheus] Allow configuring metrics prefix through a fla…

…g. (cloudprober#732)

- Add a new flag `--prometheus_metrics_prefix` to set metrics prefix for
 the prometheus surfacer.

- In a typical multi-tenant deployment, one would want to set metrics
prefix for all tenants. Since configs are usually tenant specific,
configs are not a good place for that, while binary flags are usually
controlled by the operator, making them a good place for such settings.

Fix client cert handling when cert reloading is enabled (cloudprober#697

)

Since cloudprober is the client, the dynamic cert loading needs to be
implemented in GetClientCertificate rather than GetCertificate.