[Performance improvements for find/install] Refactor Find to use IRepositorySearch

[SydneyhSmith]

Summary of the new feature / enhancement

• Find is inconsistently used, and server APIs sometimes called directly for same purpose.
  This makes it impossible to add a simple client side cache to cover cases:
  Find-PSResource -Name Az* -Repository PSGallery -SkipPublishersCheck:$false
• Need to have clean serach interface that covers all search scenarios:
• IRepositorySearch
• Find(repositoryName, string packageName) -> Find latest version single pkg (no wild card)
• Find(repositoryName, string[] packageName) -> Find latest version of multiple pkg names (wildcard supported)
• Find(repositoryName, string packageName, version) -> Find single pkg with version (no wild card)
• Find(repositoryName, string[] packageName, version) -> Find multiple pkg names with version (wildcard supported)
• FindAll() ->
• IRepositoryPackage
• GetPackage(repositoryName, string packageName)
• GetPackage(repositoryName, string[] packageName)
• GetPackage(repositoryName, string[] package, version)
• Dependency search does not use Find method, but calls nuget search APIs directly.

Proposed technical implementation details (optional)

No response

[alerickson]

Closing this issue in favor of #746