feat: define essential container spec parameters

pkg/api/resources.go

@@ -0,0 +1,14 @@
+package api
+
+type CPUResources struct {
+	// Limit is the maximum amount of CPU nanocores (1000000000 = 1 CPU core) the container can use.
+	Limit int64
+}
+
+type MemoryResources struct {
+	// Limit is the maximum amount of memory (in bytes) the container can use.
+	Limit int64
+	// Reservation is the minimum amount of memory (in bytes) the container needs to run efficiently.
+	// TODO: implement a placement constraint that checks available memory on machines.
+	Reservation int64
+}