Refactor search result components

Created by: limitedmage

Our search result components have some technical debt that needs to be fixed.

• Split SearchResult into RepoSearchResult and CommitSearchResult components - #34804
• Rename FileMatch to FileSearchResult - #34805
• Refactor CommitSearchResultMatch to a function component - #34935
• Refactor CodeExcerpt to a function component - #35881
• Rename RepoIcon to CodeHostIcon - #35891
• Move FileSearchResult and all the components only it depends on from shared to search-ui package - #35903
• Factor out any common UI between RepoSearchResult, CommitSearchResult, and FileSearchResult into a new SearchResult component. Or put more stuff into the existing ResultContainer. - #35982