fix: Adjust filtering logic for secure contexts; improve tests

[acul71]

Title

fix: Update filtering logic to respect secure contexts and enhance related tests

Description

This PR addresses issue #564 by modifying the multiaddr filtering logic in the trustless-gateway module to ensure that allowInsecure: false respects Secure Contexts.

Changes Made:

IP Address Filtering:
Modified the filter to ensure that when allowInsecure is false, a multiaddr with "127.0.0.1" as the IP address will still be considered valid. This addresses the need to handle secure contexts properly even when allowInsecure is disabled.
Domain Filtering:
Adjusted the filter to ensure that when allowInsecure is false, a multiaddr with "localhost" as the domain will be treated as valid.
Updated the filter to handle domains with a parent domain of "localhost", such as example.localhost, foobar.localhost, and *.localhost.

// When allowInsecure is false and allowLocal is true, allow multiaddrs with "127.0.0.1", "localhost", or any subdomain ending with ".localhost"
    if (!allowInsecure && allowLocal) {
      if (ma.toOptions().host === '127.0.0.1' || ma.toOptions().host === 'localhost' || ma.toOptions().host.endsWith('.localhost'))
        return true
    }

Tests Added:

Added tests to verify that the changes work as intended:
IP Address Test: Ensures that "127.0.0.1" is treated correctly when allowInsecure is false.
Domain Test: Verifies that "localhost" and parent domains of "localhost" are handled correctly when allowInsecure is false.
Related: GitHub Issue #564

  it('filterNonHTTPMultiaddrs allows 127.0.0.1 when allowInsecure=false', async function () {
    const localMaddr = uriToMultiaddr('http://127.0.0.1')

    const filtered = filterNonHTTPMultiaddrs([localMaddr], false, true)

    expect(filtered.length).to.deep.equal(1)
  })

  it('filterNonHTTPMultiaddrs allows localhost when allowInsecure=false', async function () {
    const localMaddr = uriToMultiaddr('http://localhost')

    const filtered = filterNonHTTPMultiaddrs([localMaddr], false, true)

    expect(filtered.length).to.deep.equal(1)
  })

  it('filterNonHTTPMultiaddrs allows *.localhost when allowInsecure=false', async function () {
    const localMaddr = uriToMultiaddr('http://example.localhost')

    const filtered = filterNonHTTPMultiaddrs([localMaddr], false, true)

    expect(filtered.length).to.deep.equal(1)
  })

Notes & open questions

None at the moment. The changes have been tested and are working as expected.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works

[SgtPooki]

lgtm, one suggested improvement. thanks a ton for throwing this together :)