Proper releases

[benbz]

• Proper versioning in Chart.yaml for the chart and Jitsi itself
• Create tags for releases rather than referring to individual commits
• Automation to turn a tag/release into a Helm chart repo
• Generate changelog and upgrade notes

[Arkaniad]

Some notes on this:

For tagged releases / chart repo process we can use chart-releaser (via the Github Action) and use Github Pages to deploy the repo.

Might also be worth adding chart-testing as well even if just for linting purposes initially.

[benbz]

CI / Liniting is #32 FWIW

[benbz]

Reopening as #40 only did one bullet point

[gaelgatelement]

Last point will be blocked on helm/chart-releaser#241