[epic] Migration Tasks for Plugin-arched PipeCD

[t-kikuc]

What would you like to be added:

This issue tracks ALL tasks for migrating to the pipedv1.
When a new task or PR emerges, please add/link it to this PR.

Why is this needed:

• To make existing applications available in pipedv1
• To complete the migration without omission
• To make it easier to migrate for users (both Control Plane owners and Piped managers)

Tasks

DB in Control Plane

• migrate Application's PlatformProvider to the set of plugins and deployTargets

Config files

• convert PlatformProvider to deployTargets

  • PlatformProvider.type → plugin name
  • PlatformProvider.name → deployTarget name

• Piped Config

  • analysisProvider: Move to under plugins of Analysis

• Application Config

  • skipOn: Update indent of skipOn

Docs

• TBA