This change adds the following to the list branches api:
- 'query' parameter for querying branches using arbitrary substrings
- 'sort' parameter for sorting the branches (name and date supported)
- 'direction' parameter for specifing the direction of the sorted output
This commit has the following changes:
- API for listing branches
- Improve performance of content API for dir type responses with includeCommit=true
- swagger for git operations
- fix file names from camelCase to kebab_case
