Add atmos vendor commands. Add atmos vendor pull command. Improve error messages. Cleanup code

[aknysh]

what

• Add atmos vendor commands
• Add atmos vendor pull command
• Improve error messages
• Cleanup code

why

• atmos vendor commands are used to manage vendoring for components and stacks
• atmos vendor pull -c <component> command pulls sources and mixins for the specified component
• Support k8s-style YAML config (file component.yaml) to describe component vendoring configuration. The file is placed into the component folder and then the atmos command atmos vendor pull -c <component> is executed to pull the sources and mixins for the component

component.yaml

apiVersion: atmos/v1
kind: ComponentVendorConfig
metadata:
  name: vpc-flow-logs-bucket-vendor-config
  description: Source and mixins config for vendoring of 'vpc-flow-logs-bucket' component
spec:
  source:
    # 'uri' supports all protocols (local files, Git, Mercurial, HTTP, HTTPS, Amazon S3, Google GCP),
    # and all URL and archive formats as described in https://github.com/hashicorp/go-getter
    # In 'uri', Golang templates are supported  https://pkg.go.dev/text/template
    # If 'version' is provided, '{{.Version}}' will be replaced with the 'version' value before pulling the files from 'uri'
    uri: github.com/cloudposse/terraform-aws-components.git//modules/vpc-flow-logs-bucket?ref={{.Version}}
    version: 0.194.0
    # Only include the files that match the 'included_paths' patterns
    # If 'included_paths' is not specified, all files will be matched except those that match the patterns from 'excluded_paths'
    # 'included_paths' support POSIX-style Globs for file names/paths (double-star `**` is supported)
    # https://en.wikipedia.org/wiki/Glob_(programming)
    # https://github.com/bmatcuk/doublestar#patterns
    included_paths:
      - "**/*.tf"
      - "**/*.tfvars"
      - "**/*.md"
    # Exclude the files that match any of the 'excluded_paths' patterns
    # Note that we are excluding 'context.tf' since a newer version of it will be downloaded using 'mixins'
    # 'excluded_paths' support POSIX-style Globs for file names/paths (double-star `**` is supported)
    excluded_paths:
      - "**/context.tf"

  # mixins override files from 'source' with the same 'filename' (e.g. 'context.tf' will override 'context.tf' from the 'source')
  # mixins are processed in the order they are declared in the list
  mixins:
    # https://github.com/hashicorp/go-getter/issues/98
    - uri: https://raw.githubusercontent.com/cloudposse/terraform-null-label/0.25.0/exports/context.tf
      filename: context.tf
    - uri: https://raw.githubusercontent.com/cloudposse/terraform-aws-components/{{.Version}}/modules/datadog-agent/introspection.mixin.tf
      version: 0.194.0
      filename: introspection.mixin.tf

• The URIs (uri) in the vendoring config support all protocols (local files, Git, Mercurial, HTTP, HTTPS, Amazon S3, Google GCP), and all URL and archive formats as described in https://github.com/hashicorp/go-getter

• included_paths and excluded_paths support POSIX-style Globs for file names/paths (double-star ** is supported as well)

test

atmos vendor pull -c infra/vpc-flow-logs-bucket

Pulling sources for the component 'infra/vpc-flow-logs-bucket' 
from 'github.com/cloudposse/terraform-aws-components.git//modules/vpc-flow-logs-bucket?ref=0.194.0' 
and writing to 'examples/complete/components/terraform/infra/vpc-flow-logs-bucket'

Including the file 'README.md' since it matches the '**/*.md' pattern from 'included_paths'
Excluding the file 'context.tf' since it matches the '**/context.tf' pattern from 'excluded_paths'
Including the file 'default.auto.tfvars' since it matches the '**/*.tfvars' pattern from 'included_paths'
Including the file 'main.tf' since it matches the '**/*.tf' pattern from 'included_paths'
Including the file 'outputs.tf' since it matches the '**/*.tf' pattern from 'included_paths'
Including the file 'providers.tf' since it matches the '**/*.tf' pattern from 'included_paths'
Including the file 'variables.tf' since it matches the '**/*.tf' pattern from 'included_paths'
Including the file 'versions.tf' since it matches the '**/*.tf' pattern from 'included_paths'

Pulling the mixin 'https://raw.githubusercontent.com/cloudposse/terraform-null-label/0.25.0/exports/context.tf' 
for the component 'infra/vpc-flow-logs-bucket' 
and writing to 'examples/complete/components/terraform/infra/vpc-flow-logs-bucket'

Pulling the mixin 'https://raw.githubusercontent.com/cloudposse/terraform-aws-components/0.194.0/modules/datadog-agent/introspection.mixin.tf' 
for the component 'infra/vpc-flow-logs-bucket' 
and writing to 'examples/complete/components/terraform/infra/vpc-flow-logs-bucket'

[nitrocode]

Looks good to me.