switch envs, resources are shared on multiple envs and are exclusive

[dnsi0]

Fixes #1280 .

Changes proposed in this PR:

• Introduces a C2DEnvironmentConfig type and separates environment-specific configuration (fees, access, resource limits, job durations) from the Docker engine-level configuration (socket, resources, image settings)
• Each Docker engine now supports multiple named environments via an environments: [] array, each with its own fees, access control, and resource constraints
• Engine-level resources (CPU, RAM, GPU, disk) are shared across all environments; an environment can optionally
  reference a subset of engine resources by ID
• Adds C2DEnvironmentConfigSchema with validation: each environment must define either a fees or free configuration, and storageExpiry must be ≥ maxJobDuration
• Fee processing and resource building are extracted into dedicated private methods (processFeesForEnvironment,
  buildEnvResources), replacing the previous monolithic single-environment startup logic

[alexcos20]

we plan to have global resources? then how do you limit them in an env?