Include default named trust stores in notation.

[priteshbandi]

Desire : As part of notation we would like to add publicly trusted codesigning roots as a named trust-store that can be readily used by consumers.

Expected Outcome: An agreed upon source where publicly trusted roots can be pulled from; A mechanism to monitor and ensure all changes to this list are approved by the WG

Additional Context :
Need to establish a governance framework on criteria used to have something included in the default trust store

[iamsamirzon]

Related to : notaryproject/specifications#144

[iamsamirzon]

Based on the agreement in NV2 community call on 12/5/2022, moving this out of RC-2