Add revdep calculation

Add CompilationSpecs type to handle slices of CompilationSpec, to
perform operation such as Unique() and Remove().

Add also dependencies and the spec associated to the Artifact, to track
how the artifact was generated.

Add revdeps compilation wrapper, and unit tests

pkg/compiler/interface.go

@@ -17,11 +17,14 @@ package compiler
 
 import (
 	pkg "github.com/mudler/luet/pkg/package"
+	"github.com/mudler/luet/pkg/solver"
 )
 
 type Compiler interface {
 	Compile(int, bool, CompilationSpec) (Artifact, error)
-	CompileParallel(concurrency int, keepPermissions bool, ps []CompilationSpec) ([]Artifact, []error)
+	CompileParallel(concurrency int, keepPermissions bool, ps CompilationSpecs) ([]Artifact, []error)
+	CompileWithReverseDeps(concurrency int, keepPermissions bool, ps CompilationSpecs) ([]Artifact, []error)
+
 	FromPackage(pkg.Package) (CompilationSpec, error)
 
 	SetBackend(CompilerBackend)
@@ -50,6 +53,13 @@ type CompilerBackend interface {
 type Artifact interface {
 	GetPath() string
 	SetPath(string)
+	GetDependencies() []Artifact
+	SetDependencies(d []Artifact)
+	GetSourceAssertion() solver.PackagesAssertions
+	SetSourceAssertion(as solver.PackagesAssertions)
+
+	SetCompileSpec(as CompilationSpec)
+	GetCompileSpec() CompilationSpec
 }
 
 type ArtifactNode struct {
@@ -93,3 +103,11 @@ type CompilationSpec interface {
 
 	GetPreBuildSteps() []string
 }
+
+type CompilationSpecs interface {
+	Unique() CompilationSpecs
+	Len() int
+	All() []CompilationSpec
+	Add(CompilationSpec)
+	Remove(s CompilationSpecs) CompilationSpecs
+}