Docs for v0.10.3

Point-in-time snapshot of the kagent documentation at the kagent v0.10.3 release.

Publishing this release runs Update Reference Documentation against the kagent
v0.10.3 tag and opens a pull request regenerating the 0.x API, Helm, and CLI
references along with the 0.x version conrefs. See #525 for the trigger.

First docs release cut from this repository, so there is no earlier tag to
generate a changelog from. Later releases carry the usual What's Changed list.

Full Changelog: v0.10.2...v0.10.3