feat: bump default railpack version to 0.3.0

[Marukome0743]

What is this PR about?

Bump the default railpack version from 0.2.2 to 0.3.0 throughout the application

Enhancements:

• Update default railpack version to 0.3.0 in front-end build form and server schema

Build:

• Bump Dockerfile ARG RAILPACK_VERSION to 0.3.0

Deployment:

• Update installRailpack script to set default RAILPACK_VERSION to 0.3.0

Tests:

• Update drop and traefik tests to expect railpackVersion 0.3.0

Chores:

• Update database migration snapshots to reflect new default railpack version

Checklist

Before submitting this PR, please make sure that:

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance.

[cheetahbyte]

Old migration files should never be edited. You should create a new migration which just edits the default value of this column.