Add is-abp license

[fmarier]

I have heard back from the author of the is-abp list by email and the list will be licensed under the usual EasyList license.

We can update our licensing information.

[kjozwiak]

Verification PASSED on macOS 10.15.1 x64 using the following build:

Brave	1.1.19 Chromium: 79.0.3945.70 (Official Build) (64-bit)
Revision	65868db27916cebde51fc2465c9b34761e6383e2-refs/branch-heads/3945@{#869}
OS	macOS Version 10.15.1 (Build 19B88)

• went through the STR mentioned via Improve licensing of external components brave-core#4103
• ensured that all references of EasyList have been removed from brave://credits
• ensured that Disconnect has been removed from brave://credits
• ensured HTTPS Everywhere was removed and Brave HTTPS Everywhere was added instead
• ensured that Brave Sync is still being listed under brave://credits
• ensured that the following items have been added into brave://credits as per Improve licensing of external components brave-core#4103
  • Brave Ad Block
    • ensured https://github.com/brave/brave-core-crx-packager was opened
  • Brave Ethereum Remote Client Extension
    • ensured https://github.com/brave/ethereum-remote-client was opened
  • Brave HTTPS Everywhere
    • ensured https://github.com/brave/https-everywhere-builder was opened
  • Brave Local Data
    • ensured https://github.com/brave/brave-core-crx-packager was opened
  • Brave Tor Client
    • ensured https://github.com/brave/tor_build_scripts was opened

Verification passed on

Brave	1.1.19 Chromium: 79.0.3945.70 (Official Build) (64-bit)
Revision	65868db27916cebde51fc2465c9b34761e6383e2-refs/branch-heads/3945@{#869}
OS	Ubuntu 18.04 LTS

• Verified test plan from Improve licensing of external components brave-core#4103
• Verified is-abp license is included

Verification passed on

Brave	1.1.19 Chromium: 79.0.3945.70 (Official Build) (64-bit)
Revision	65868db27916cebde51fc2465c9b34761e6383e2-refs/branch-heads/3945@{#869}
OS	Windows 7 Service Pack 1 (Build 7601.24530)

• Verified test plan from Improve licensing of external components brave-core#4103
• Verified is-abp license is included