Migrate Docker images to swmansion/pathfinder

[franciszekjob]

Following the project ownership transfer, swmansion/pathfinder becomes the canonical Docker Hub repository.

This PR:

• publishes images to swmansion/pathfinder
• mirrors newly published images to eqlabs/pathfinder during the transition period
• updates docs
• updates the release workflow to dispatch version updates to software-mansion/pathfinder-infra.

Temporary mirroring should be removed after the migration window, as described in #3563. Historical tags are migrated separately.

[franciszekjob]

I verified the mirroring workflow (most importantly the mirroring step) in franciszekjob/dockerhub-mirror-test using separate Docker Hub accounts (to simulate our case).

The test covered snapshot publishing and a release creating and mirroring v0.0.1 and latest. Both tags have the same digest in the primary and legacy repositories:

sha256:5106d9f7fc50c51d036dc7a0a52c073ecb548145987eda2f43a75c67022f913f

[franciszekjob]

note: I've added EQLABS_* secrets to our repo. Before/after merging this PR I will also update DOCKER_HUB_USERNAME and DOCKER_HUB_ACCESS_TOKEN.