add(gitea-api): issues and milestones getters

This implements the api getters for extracting the issues and milestones
for a given gitea repository. WIP for #1.

internal/gitea/repository.go

@@ -0,0 +1,17 @@
+package gitea
+
+import "fmt"
+
+type Repository struct {
+	Id        uint
+	Name      string
+	Owner     string
+	Full_name string
+}
+
+func NewRepository(name, owner string) (repo Repository) {
+	repo.Name = name
+	repo.Owner = owner
+	repo.Full_name = fmt.Sprintf("%s/%s", owner, name)
+	return
+}