Dispatch 0.7.0

What's Changed

• Block outbound-port-25 SMTP relays on Azure by @chrismuench in #8
• Attach virtual-appliance images to the release by @chrismuench in #9
• fix(appliance): make the Pester Copy-Item mock satisfy the script's copy guard by @chrismuench in #13
• Multi-database support: bundled SQLite default, plus PostgreSQL / MariaDB / SQL Server by @chrismuench in #14
• Data layer: security + performance review fixes by @chrismuench in #15
• Measure the pooling fix through production - it's ~1.2x, correcting the comments by @chrismuench in #16
• Add a cross-engine regression guard for the UTC timestamp fix by @chrismuench in #17
• Characterise scale on all four engines by @chrismuench in #18
• Join the dashboard list to its dedup set instead of IN(subquery) by @chrismuench in #19
• Cover every Message Log filter (include + exclude, both read paths) by @chrismuench in #20
• Prepare the 0.7.0 release by @chrismuench in #21

Full Changelog: v0.5.0...v0.7.0

Dispatch 0.5.0

Full Changelog: https://github.com/CinderHillsDev/dispatch-platform/commits/v0.5.0