Add backend support for specifying target type [RUN ALL RSPEC] [RUN AS-IF-FOSS]

What does this MR do?

adds the ability to set target_type on DastSiteProfile and retrieve the value via GraphQL.

Why?

we want to give users of dast on-demand scans the ability to run api scans.

Related Issue(s)

• #294060 (closed)

GraphQL

enable the feature in the rails console with:

Feature.enable(:security_dast_site_profiles_api_option) 

Query

{
  project(fullPath: "root/on-demand-scans") {
    dastSiteProfiles(first: 3) {
      nodes {
        id
        targetType
      }
    }
  }
}

Mutation

query:

mutation($dastSiteProfileCreateInput: DastSiteProfileCreateInput!) {
  dastSiteProfileCreate(input: $dastSiteProfileCreateInput) {
    clientMutationId
    errors
    id
  }
}

variables:

{
  "dastSiteProfileCreateInput": {
    "fullPath": "namespace1/project1",
    "profileName": "Total impactful access",
    "targetUrl": "http://example1.test",
    "targetType": "API",
    "excludedUrls": [
      "http://example1.test/logout"
    ],
    "requestHeaders": "Authorization: secret",
    "auth": {
      "enabled": true,
      "url": "http://example1.test/login",
      "usernameField": "session[username]",
      "passwordField": "session[password]",
      "username": "user3@example.org",
      "password": "24156abc1b46755ca3a2a2ffa566ea9b"
    }
  }
}

Database

% rails db:migrate:up VERSION=20210407002511 && rails db:migrate:down VERSION=20210407002511                                                                                                                                                                                                                                                                                    
== 20210407002511 AddTypeToDastSiteProfile: migrating =========================
-- add_column(:dast_site_profiles, :target_type, :integer, {:limit=>2, :default=>0, :null=>false})
   -> 0.0073s
== 20210407002511 AddTypeToDastSiteProfile: migrated (0.0073s) ================

== 20210407002511 AddTypeToDastSiteProfile: reverting =========================
-- remove_column(:dast_site_profiles, :target_type, :integer, {:limit=>2, :default=>0, :null=>false})
   -> 0.0034s
== 20210407002511 AddTypeToDastSiteProfile: reverted (0.0057s) ================

Does this MR meet the acceptance criteria?

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Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

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• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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