[Merge when releasing ske 0.7.0] docs: release notes for upcoming 0.7.0 ske

[ChunyiLyu]

Description

Relates to https://github.com/syntasso/kratix/issues/258

Adding release notes for ske 0.7.0. This is not out yet. We should only merge it after releasing 0.7.0

Checklist

• [x] Is this PR about a feature in an upcoming SKE release? This PR updates release notes for ske 0.7.0. Added features are based on ske 0.7.0-rc2, which is likely going to be promoted to 0.7.0.
• [ ] Have you cut that new SKE release? Not yet.
• [x] Have you updated the release notes?

[richcooper95]

Pulled changes into https://github.com/syntasso/kratix-docs/pull/135 so closing this PR 🧹