Add DAP server

[rentziass]

This adds a DAP server to the runner to build debugging functionalities. The whole DAP integration is gated by the new EnableDebugger flag on the job message (feature flagged at the API level).

When a job starts, after the job setup we will start the DAP server and allow users to step over to every step in the job, and:

• inspect the scope of the runner
• test evaluating expressions
• run shell commands as if they were run steps in their jobs (full job context, supporting expression expansion, etc.)

Here's an example of what this looks like connecting to the runner from nvim-dap:

[TingluoHuang]

this feels like a parsed json?

[TingluoHuang]

or the workflow - run step?

[TingluoHuang]

run: {"command": "echo $foo", env: {....}}

[rentziass]

Let's move this to a bigger conversation but good call, something recognizable like run() + JSON as the arg would save us a lot of parsing work. I liked the ruby-ness of it in the console but truth we'll probably have tools that make these calls on behalf of users.

[ChristopherHX]

I believe you could also handle additionally action yml snippets (vscode shift enter for multiline input, not unlikely nvim-dap can as well)

run
- run: |
    echo Test

• Runner.Worker has a steps yaml parser for this
• Can be detected by run followed by newline
• Similar to the lldb script command that can be followed by multiline python code

A single line fallback is always good, but for some advanced users is copy paste actual actions workflow yaml possibly a big usability win

Single line could look like this if we omit the list - or []

run { run: echo Test, env: { a: b }}

Multiline without list

run
run: |
   echo Test