Support OS level targeting for ads

[mandar-brave]

This is dependent on parsing the new catalog in #5231. CreativeSets now include a field for "oses" shows a list of OS levels (MACOS, IOS, LINUX, WINDOWS, ANDROID, ignore case). If this field is empty, assume all OSes are available. If the list is not empty, only show the ads in the creativeset if the current browser OS matches one given in the list.

[tmancey]

CI passed on all platforms other than macOS so restarting macOS

[LaurenWags]

Verified passed with

Brave	1.3.94 Chromium: 79.0.3945.117 (Official Build) beta (64-bit)
Revision	04f0a055010adab4484f7497fbfdbf312c307f1d-refs/branch-heads/3945@{#1019}
OS	macOS Version 10.14.6 (Build 18G103)

• Verified v2 of catalog contains the oses field referenced from description
• Confirmed that only ads where oses listed macOS or were blank were shown on macOS (no Linux or Windows ads shown)

example from staging catalog:

ad notification shown:

logs displayed:

Verification is in-progress

Brave	1.3.94 Chromium: 79.0.3945.117 (Official Build) beta (64-bit)
Revision	04f0a055010adab4484f7497fbfdbf312c307f1d-refs/branch-heads/3945@{#1019}
OS	Windows 10 OS Version 1803 (Build 17134.1006)

• Verified V2 catalog contains the oses field referenced from description
• Verified "oses" list is empty in production, viewed an ad confirmed ad triggered from multiple matching segments
  Production:
  

[4812:15912:0120/195121.492:INFO:ads_impl.cc(344)] Browser state changed to unidle
[4812:15912:0120/195121.531:INFO:ads_impl.cc(1041)] Serving ad from categories:
[4812:15912:0120/195121.531:INFO:ads_impl.cc(1043)]   business-business
[4812:15912:0120/195121.531:INFO:ads_impl.cc(1043)]   travel-travel
[4812:15912:0120/195121.531:INFO:ads_impl.cc(1043)]   technology & computing-programming
[4812:15912:0120/195121.531:INFO:client.cc(574)] Successfully saved client state
[4812:15912:0120/195121.532:INFO:ads_impl.cc(1057)] Found 2 eligible ads
[4812:15912:0120/195121.532:INFO:ads_impl.cc(1305)] Ad notification shown:
  id: eb556f9a-7664-4cc5-a6be-4a34439258da
  campaign_id: 1cd20068-1ed5-4160-98b4-453d8071e516
  advertiser: Portland State University
  category: technology & computing-programming
  text: Get ahead with our online Business Blockchain Program.
  url: https://www.pdx.edu/sba/business-blockchain-certificate-brave
  uuid: 262e23ef-2d3a-4a75-9427-430ac4edc390
[4812:15912:0120/195121.532:INFO:notifications.cc(262)] Saving notifications state
[7968:428:0120/195121.533:INFO:confirmations_impl.cc(1038)] Confirm ad:
  id: eb556f9a-7664-4cc5-a6be-4a34439258da
  creative_set_id: 39deb5f6-b62e-4277-a786-1f61ce82145a
  advertiser: Portland State University
  category: technology & computing-programming
  text: Get ahead with our online Business Blockchain Program.
  url: https://www.pdx.edu/sba/business-blockchain-certificate-brave
  uuid: 262e23ef-2d3a-4a75-9427-430ac4edc390
  type: view

Staging:

• Confirmed that only ads where oses listed windows or were blank were shown on windows
  

Verification passed on

Brave	1.3.96 Chromium: 79.0.3945.130 (Official Build) beta (64-bit)
Revision	e22de67c28798d98833a7137c0e22876237fc40a-refs/branch-heads/3945@{#1047}
OS	Ubuntu 18.04 LTS

• Verified v2 of catalog contains the oses field referenced from description
• Confirmed that only ads where oses listed linux or were blank were shown on Linux only

example from staging catalog: