fix(dashmate): dapi kills host machine on container stop

[shumkov]

Issue being fixed or feature implemented

To scale (run multiple instances) DAPI we currently using PM2 (process manager based on Node.JS custer) inside Docker container. It starts multiple processes inside one container.
This approach has multiple downsides:

1. Killing host machine on container stop
2. Additional layer of balancing while we already have Envoy as a load balancer
3. Violate Docker philosophy: 1 container - 1 process
4. ...

What was done?

• Use Docker Compose deploy replicas functionality to start multiple containers with dashmate
• Added platform.dapi.api.docker.deploy.replicas option to configure the number of DAPI instances (1 by default)
• Ignored .env that invalidates docker build cache
• Moved migration test to the proper location (according to the source directory)

Fixed already-known flaky issues to make CI green:

• Fixed --wait-for-readiness not waiting for DAPI availability
• Fixed Core RPC timeout on start
• Fixed DAPI connection handling with Tenderdash

How Has This Been Tested?

With local network

Breaking Changes

None

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or updated relevant unit/integration/functional/e2e tests
• I have added "!" to the title and described breaking changes in the corresponding section if my code contains any
• I have made corresponding changes to the documentation if needed

For repository code-owners and collaborators only

• I have assigned this pull request to a milestone

[markin-io]

utACK