style: restructure makefile (#4)

Currently, the `Makefile` is not well structured, and does not follow best practices. With the help of [`checkmake`](https://github.com/checkmake/checkmake), the Makefile can be forced to follow them.

### Decisions

- Added CI job `lint-makefile`, which forces the Makefile to conform to standards.
- The `make help` was set as the default target. This is common practice in the industry.
- The `make help` uses `grep` | `awk` to create a command table from `##` comments after each target. It seems a bit icky, but it is something that Docker, Kubernetes, and Helm all do.

Reviewed-on: #4
Co-authored-by: M.V. Hutz <git@maximhutz.me>
Co-committed-by: M.V. Hutz <git@maximhutz.me>

.gitea/workflows/ci.yml

@@ -6,8 +6,8 @@ on:
   pull_request:
 
 jobs:
-  lint:
-    name: Golang Lint
+  lint-go:
+    name: Go Lint
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -23,7 +23,7 @@ jobs:
         with:
           version: latest
 
-  unit-test:
+  test-unit:
     name: Unit Tests
     runs-on: ubuntu-latest
     steps:
@@ -34,9 +34,9 @@ jobs:
           go-version-file: go.mod
 
       - name: Run unit tests
-        run: go test ./... -cover -v
+        run: make test-unit
 
-  fuzz-test:
+  test-fuzz:
     name: Fuzz Tests
     runs-on: ubuntu-latest
     steps:
@@ -47,12 +47,9 @@ jobs:
           go-version-file: go.mod
 
       - name: Run fuzz tests
-        run: |
-          for func in $(grep -r --include='*_test.go' -oh 'func Fuzz\w*' . | sed 's/func //'); do
-            go test ./... -fuzz="^${func}$" -fuzztime=30s
-          done
+        run: make test-fuzz
 
-  mutation-test:
+  test-mutation:
     name: Mutation Tests
     runs-on: ubuntu-latest
     steps:
@@ -66,4 +63,4 @@ jobs:
         run: go install github.com/go-gremlins/gremlins/cmd/gremlins@latest
 
       - name: Run mutation tests
-        run: gremlins unleash
+        run: make test-mutation