Use knope bot for release management

[lukasIO]

uses knope and it's accompanying bot (this is a github app that needs to be installed on the repo) for release management

Also makes the release workflows less stateful and allows manual triggering of the release workflows with a dry-run option (thanks to @ladvoc for that initial idea!)

One big difference is that knope only automates

• versioning
• change documentation
• github releases

It doesn't do any release publishing to the package repositories itself. So we stay in full control of that step (pushing releases to cargo/npm) so there are less surprises in how/what the tool itself supports in this step.

For the FFI release: after merging the release preview PR the github release will be marked as draft automatically by knope until it gets edited after the artifacts have been uploaded successfully

note: tag formatting changes slightly with this change from e.g.
rust-sdks/livekit-ffi@0.12.48 to
livekit-ffi/v0.12.48