Set versioning based on CHANGELOG

[helin24]

There are several things happening here:

• Use semver format for CHANGELOG - this makes it easier to use the gradle changelog plugin, so we don't have to define a custom regex for our versioning.
• Set release version from CHANGELOG - as long as we update the changelog as part of the release process, we won't have to separately set the version in gradle.properties. The two should match during a release anyway.
• Set dev version from CHANGELOG - this means we won't need to update a hard coded version in the deploy script.

(will rebase after #8455)

Addresses #8417