Release Crossplane version v1.15

[plumbis]

• Update the $LATEST_VER parameter in netlify_build.sh
• Update params.latest in config.yaml
• Update version in the _index.md file of /content/<new latest>
• Copy Crossplane cluster/crds contents to /content/<new latest>/api/yaml.
• Create a new release/tag named "v-archive" to snapshot EOL'd docs.
• Remove EOL'd docs version from "/content" directory and run hugo locally to check for broken links.
• Trigger Algolia Crawler after publishing to reindex results.

PR #701
For crossplane/release#2

[plumbis]

Closing as complete.