Rework conditions

[Fizzadar]

WIP! New conditions implementation that actually makes sense:

name: my-project
configVersion: 1
requireKubetools: '~=12.0'  # optional, replacement for minKubetoolsVersion

deployments:
  app-name:
    conditions:
      dev:  true  # default
      test: true  # default
      deploy:
        - env: 'production'
          namespace: 'A'
        - env: 'backup'
          namespace: 'B'

Closes: #64