introduce self-contained to headless

[dogancanbakir]

Proposed changes

$ cat test.yaml 
id: piratebay

info:
  name: piratebay
  author: philippedelteil
  severity: info

self-contained: true

headless:
  - steps:
      - args:
          url: 'https://thepiratebay.org/search.php?q=user:{{user}}'
        action: navigate

      - action: waitload
    matchers:
      - type: dsl
        dsl:
          - "!contains(data,'No results returned')"

$ go run . -t test.yaml -headless -var user=zheega

                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.0.2

                projectdiscovery.io

[INF] Current nuclei version: v3.0.2 (latest)
[INF] Current nuclei-templates version: v9.6.8 (latest)
[INF] New templates added in latest release: 79
[INF] Templates loaded for current scan: 1
[WRN] Executing 1 unsigned templates. Use with caution.
[piratebay] [headless] [info] https://thepiratebay.org

Closes #4057.

Checklist

• Pull request is created against the dev branch
• All checks passed (lint, unit/integration/regression tests etc.) with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[Mzack9999]

lgtm - I noticed in the matcher we return only the base url instead of the full one (I changed the url to http://localhost:8000 with simplehttpserver)

With self-contained:

$ go run . -t test.yaml -headless -var user=zheega
...
[piratebay] [headless] [info] http://localhost:8000

Without:

$ go run . -t test.yaml -headless -var user=zheega -u "http://localhost:8000/search.php?q=user:{{user}}"
...
[piratebay] [headless] [info] http://localhost:8000/search.php?q=user:{{user}}

[dogancanbakir]

Fixed:

$ go run . -t test.yaml -headless -var user=zheega

                     __     _
   ____  __  _______/ /__  (_)
  / __ \/ / / / ___/ / _ \/ /
 / / / / /_/ / /__/ /  __/ /
/_/ /_/\__,_/\___/_/\___/_/   v3.0.2

                projectdiscovery.io

[INF] Current nuclei version: v3.0.2 (latest)
[INF] Current nuclei-templates version: v9.6.8 (latest)
[INF] New templates added in latest release: 79
[INF] Templates loaded for current scan: 1
[WRN] Executing 1 unsigned templates. Use with caution.
[piratebay] [headless] [info] https://thepiratebay.org/search.php?q=user:zheega