feat(action): auto-discovery of deno.json and auto-populate defaults

Closes #350 **Features:** - Add a new option `deno-config` - Auto-discovery of `deno.json`/`deno.jsonc` from the root file - If the deno config file exists, then - `project` defaults to `"deploy.project"` - `entrypoint` defaults to `"deploy.entrypoint"` - `exclude` defaults to `"deploy.exclude"` - `include` defaults to `"deploy.include"` - `import-map` defaults to `"importMap"` - If it contains a `"import"` field, it is saved as JSON to `import-map-autogen-temp`, allowing use of JSONC deno config file since using them directly in `import-map` would cause parsing issues if there is comments **Changes:** - Added `jsonc` as dependency - Modified the workflow to have the test project as variable so it's easier for contributor to test their code - Updated docs about the new `deno-config` feature - Added a new test case to cover this new feature