Adds basic support for pre/post-deployment commands.

[stooit]

Runs a given command (or script) in a named container on applications after a deployment has completed. Largely replaces the need for custom entrypoints.

Also adds support for running pre-deployment commands to run in the existing container prior to new ones spinning up.

Some notes:

• Applications only, no services support
• Applications that do not support rolling deployments with health checks (e.g docker compose) may not be healthy, script/command would need to account for that

[RayBB]

Nice! This also might help with https://github.com/coollabsio/coolify/issues/1688#issue-2105964566

[kfranckiewicz]

I missed this feature. Also I can't wait merge this PR. @stooit have You idea how can testing this without merge PR ? I see that You have configured healthcheck. Can You share a screenshot your configuration cause I have same problem with this configuration.

[andrasbacsai]

Huge! I will test it! Thank you!