This MR adds more information into the summary view, including the MR author, created at date, merge status, draft status, conflicts, and pipeline status, among other things. This is configurable via the setup function.
This MR adds a Lua test suite to the project, run via busted, and introduces tests for a number of the utility functions. Subsequent work will have to be done to test functions that use the `vim.api` scope and external packages to the plugin.
