docker: add Cosmovisor for automated chain upgrades

[diorwave]

Adds Cosmovisor (pinned v1.7.0) to the layerd image so governance upgrades swap the binary at the upgrade height automatically.

• Dockerfile: builds Cosmovisor into the image; sets DAEMON_NAME=layerd, DAEMON_RESTART_AFTER_UPGRADE=true, DAEMON_ALLOW_DOWNLOAD_BINARIES=false.

Important:

• Auto-download is OFF pre-stage each upgrade binary at $DAEMON_HOME/cosmovisor/upgrades/<name>/bin/layerd.
• Mount a volume at $DAEMON_HOME/cosmovisor to persist upgrades.
• Backwards compatible; start flags pass through unchanged.

Built + smoke-tested (init seeds genesis bin, start runs via Cosmovisor); not yet deployed.

[krasi-georgiev]

Please remove all changes that are not relevant to the pr title

[diorwave]

removed all the unrelated changes, the pr is now just the 2 docker files (dockerfile + docker/entrypoint.sh)
It adds cosmovisor(pinned v1.7.0) to the image so chain upgrades are applied automatically at the upgrade height instead of manually swapping the binary
auto-download is off (binaries are pre-staged), and DAEMON_HOME is derived from --home