api/auth: Allow authorization to be used for viewership metrics API

[victorges]

What does this pull request do? Explain your changes. (required)
This allows the authorization API, currently used for stream health, to also
be used for the viewership API. This mostly means adding support for authorizing
access to a given asset as well, not only to a stream. Also adding CORS support
on the analyzer endpoint.

This goes together with livepeer/livepeer-data#60

Specific updates (required)

• Allow auth API to receive an asset ID not only a stream ID
• Allow CORS on the viewership API

-

• How did you test each of these updates (required)
• yarn test
• also deployed to staging to check functionality

Does this pull request close any open issues?
Closes #1278

Checklist:

• I have read the CONTRIBUTING document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.

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Name	Status	Preview	Updated
livepeer-studio	✅ Ready (Inspect)	Visit Preview	Sep 16, 2022 at 9:50PM (UTC)

[codecov]

Codecov Report

Merging #1279 (345898e) into master (5229117) will increase coverage by 0.31054%.
The diff coverage is 100.00000%.

@@                 Coverage Diff                 @@
##              master       #1279         +/-   ##
===================================================
+ Coverage   51.06138%   51.37192%   +0.31054%     
===================================================
  Files             66          66                 
  Lines           4334        4337          +3     
  Branches         786         786                 
===================================================
+ Hits            2213        2228         +15     
+ Misses          1842        1830         -12     
  Partials         279         279                 

Impacted Files	Coverage Δ
packages/api/src/controllers/auth.ts	100.00000% <100.00000%> (+80.00000%)	⬆️
packages/api/src/middleware/auth.ts	91.34615% <100.00000%> (+3.72709%)	⬆️

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Impacted Files	Coverage Δ
packages/api/src/controllers/auth.ts	100.00000% <100.00000%> (+80.00000%)	⬆️
packages/api/src/middleware/auth.ts	91.34615% <100.00000%> (+3.72709%)	⬆️

[gioelecerati]

LGTM

[adamsoffer]