* Refactor config package so default settings are always used with config file not loaded
* Update `findVersionsInDir` to check legacy files
* Refactor functions in internal/resolve package to return `ToolVersion` structs instead of version slices
* Refactor `findVersionsInEnv` function to return env variable name
* Create `resolve.Version` function
* Implement info command
* Remove duplicate and unneeded BATS tests from `main_test.go`
* remove download dir for plugin when removing plugin
* update plugins.Add function so downloads directory is created