Fix 404s in _redirects

[hbelmiro]

The following _redirects still 404:

• /docs/pipelines/pipelines-samples/ /docs/components/pipelines/build-pipeline/

  • I am not sure the best place to point this one, perhaps just /docs/components/pipelines/overview/

• /docs/components/pipelines /docs/components/pipelines/pipelines

  • This is not a 404, but a redundant redirect, so let's remove it.

• /docs/components/pipelines/caching /docs/components/pipelines/overview/caching

• /docs/components/pipelines/caching-v2 /docs/components/pipelines/overview/caching-v2

• /docs/components/pipelines/multi-user /docs/components/pipelines/overview/multi-user

• /docs/components/pipelines/pipeline-root /docs/components/pipelines/overview/pipeline-root

• /docs/components/pipelines/pipelines-quickstart /docs/components/pipelines/overview/quickstart

• /docs/pipelines/concepts/* /docs/components/pipelines/overview/concepts/:splat

  • This one will cause problems in the future, just update its target to /docs/components/pipelines/concepts (with no :spat)

• /docs/pipelines/* /docs/components/pipelines/:splat

  • This one will cause problems in the future, just update its target to /docs/components/pipelines (with no :spat)

Contextualization: #3737 (review)
Should be fixed after #3737 gets merged.

/area pipelines

[hbelmiro]

Fixed in #3737 (comment).