Pass extensions marketplace settings hash to Web IDE

MRs:

• Pass settings context hash to Web IDE (!175031 - merged)
• Web IDE Settings Sync E2E specs (!175165 - merged)

Description

We want to create a hash of the extensions marketplace settings to pass to the Web IDE as part of its configuration, which was added in Support extensions marketplace context in the W... (gitlab-web-ide#414 - closed).

Acceptance Criteria/Technical Requirements

• Create a helper method that:
  • Generates a hash of the extensions marketplace setting if it is enabled
  • Returns nil otherwise.
• Pass the extensions marketplace settings hash to the Web IDE config.
• Top o' the pyramid E2E/QA test for behavior (possibly feature).
• Once the MR to pass the settings context hash to Web IDE is merged in, test out the changes to migrate existing extensions data to new settings context by rolling out the web_ide_settings_context_hash feature flag via chatops:
  • Enable the feature globally on non-production environments with /chatops run feature set <feature-flag-name> true --dev --pre --staging --staging-ref
  • Enable in production