Address top 404s by adding redirect rules

[chalin]

There have been about 400 page not found errors in the past 30 days (which isn't too bad). For example, the link to https://opentelemetry.io/releases/ mentioned in open-telemetry/opentelemetry-java#545 no longer exists. AFAICT there are no redirect rules currently.

Top 10 404s as of 2021-08-10:

• /docs/collector/about/ - Fix import in MetricExporter to fix build. opentelemetry-java#851
• /about/ - Fix import in MetricExporter to fix build. opentelemetry-java#851
• /project-status/ - Fix import in MetricExporter to fix build. opentelemetry-java#851
• /docs/concepts/overview/ - Fix import in MetricExporter to fix build. opentelemetry-java#851
• /docs/java/
  • Waiting on [website_docs] Questions about "Getting started", and OTel website 404s for Java docs opentelemetry-java-examples#19
  • /docs/java/automatic_instrumentation/ - Return LabelSetSdk to allow using getLabels in tests and internally opentelemetry-java#868
  • /docs/java/getting_started/ - Return LabelSetSdk to allow using getLabels in tests and internally opentelemetry-java#868
• /releases/ - add the missing enclosing interface opentelemetry-java#854
• /otel - Fix import in MetricExporter to fix build. opentelemetry-java#851
• /) - won't fix
• /schemas/1.2.0; /schemas/v1.4.0 is 8th in 2021 as of Oct. 20 - won't fix because, IMHO, we want these to fail.

[chalin]

Top 10 404s as of 2021-08-10 (see opening comment for text versions of the paths):

[chalin]

For example, @alolita's Nurturing Observability with Open Source post links to /about.

[chalin]

Ah, I'm seeing that the site uses Hugo aliases. IMHO, it is better to use Netlify redirects, even the Hugo doc's does so, see https://github.com/gohugoio/hugoDocs/blob/7cc1da82e757ba2c6d4d7df3ccd01d7d1adf132a/config.toml#L17-L18

[chalin]

@austinlparker - what did /releases/ used to refer to? What could we usefully redirect it to, if at all?

[austinlparker]

I believe that went to what is now /status/.

[chalin]

@anuraaga wrote in open-telemetry/opentelemetry-java-examples#19:

I think for the quick fix we can redirect

/docs/java/getting_started/ -> https://opentelemetry.io/docs/java/manual_instrumentation/

/docs/java/automatic_instrumentation/ -> https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/README.md

Thanks for the feedback!