feat: move shareable policies out of experimental

[olblak]

This pullrequest allows to use shareable policies without specifying the flag --experimental

Test

To test this pull request, you can run the following commands

go build -o bin/updatecli . 
./bin/updatecli diff ghcr.io/updatecli/policies/nodejs/githubaction:0.4.0@sha256:aeb512401d128f791cffed7ad6c7c79c5d30c012f57e410e7cb5027f4d360833 
./bin/updatecli compose diff -f update-compose.yaml

Additional Information

Tradeoff

Potential improvement