Write some documents

[kenji-miyake]

Checklist

• I've read the contribution guidelines.
• I've searched other issues and no duplicate issues were found.
• I've agreed with the maintainers that I can plan this task.

Description

We have to explain some items:

• Types of launch files
• Usage
• Design concepts
• Global parameters

Related: autowarefoundation/autoware#194

Purpose

So that users can understand them.

Possible approaches

Just write documents.

Definition of done

• Types of launch files
• Usage
• Design concepts
• Global parameters

[stale]

This pull request has been automatically marked as stale because it has not had recent activity.

[stale]

This pull request has been automatically marked as stale because it has not had recent activity.