refactor: Create SigningDriver and CiDriver (#197)

This also includes a new `login` command. The signing and CI logic is now using the Driver trait system along with a new experimental sigstore signing driver. New static macros have also been created to make implementation management easier for `Command` usage and `Driver` trait implementation calls.

---------

Co-authored-by: xyny <60004820+xynydev@users.noreply.github.com>

test-files/github-events/branch.json

@@ -0,0 +1,10 @@
+{
+  "ref": "refs/heads/test-branch",
+  "repository": {
+    "default_branch": "main",
+    "owner": {
+      "login": "test-owner"
+    },
+    "html_url": "https://example.com/"
+  }
+}

test-files/github-events/default-branch.json

@@ -0,0 +1,10 @@
+{
+  "ref": "refs/heads/main",
+  "repository": {
+    "default_branch": "main",
+    "owner": {
+      "login": "test-owner"
+    },
+    "html_url": "https://example.com/"
+  }
+}

test-files/github-events/pr-branch.json

@@ -0,0 +1,15 @@
+{
+  "head": {
+    "ref": "test-branch"
+  },
+  "base": {
+    "ref": "main"
+  },
+  "repository": {
+    "default_branch": "main",
+    "owner": {
+      "login": "test-owner"
+    },
+    "html_url": "https://example.com/"
+  }
+}