Add automated code quality testing (#18)

* add automated code quality testing

* format

README.md

@@ -5,6 +5,7 @@
 [![Build Status](https://github.com/trixi-framework/TrixiBase.jl/workflows/CI/badge.svg)](https://github.com/trixi-framework/TrixiBase.jl/actions?query=workflow%3ACI)
 [![Coveralls](https://coveralls.io/repos/github/trixi-framework/TrixiBase.jl/badge.svg)](https://coveralls.io/github/trixi-framework/TrixiBase.jl)
 [![Codecov](https://codecov.io/gh/trixi-framework/TrixiBase.jl/branch/main/graph/badge.svg)](https://codecov.io/gh/trixi-framework/TrixiBase.jl)
+[![Aqua QA](https://raw.githubusercontent.com/JuliaTesting/Aqua.jl/master/badge.svg)](https://github.com/JuliaTesting/Aqua.jl)
 [![License: MIT](https://img.shields.io/badge/License-MIT-success.svg)](https://opensource.org/license/mit/)
 
 [TrixiBase.jl](https://github.com/trixi-framework/TrixiBase.jl) 

test/Project.toml

@@ -1,5 +1,9 @@
 [deps]
+Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
+ExplicitImports = "7d51a73a-1435-4ff3-83d9-f097790105c7"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [compat]
+Aqua = "0.7, 0.8"
+ExplicitImports = "1.0.1"
 Test = "1"

test/runtests.jl

@@ -1,5 +1,6 @@
 include("test_util.jl")
 
 @testset verbose=true "TrixiBase.jl Tests" begin
+    include("test_aqua.jl")
     include("trixi_include.jl")
 end

test/test_aqua.jl

@@ -0,0 +1,8 @@
+using Aqua: Aqua
+using ExplicitImports: check_no_implicit_imports, check_no_stale_explicit_imports
+
+@testset "Aqua.jl" begin
+    Aqua.test_all(TrixiBase)
+    @test isnothing(check_no_implicit_imports(TrixiBase))
+    @test isnothing(check_no_stale_explicit_imports(TrixiBase))
+end