Resolve "Implement interaction manipulation mechanisms"

This MR ...

• Extends the ODESystem state type to the structured BDEState type, containing B, D, and E vectors
• Implements and integrates the Environment into ODESystem
  • Controllable via the with_envmod template tag, environment interaction can now be enabled.
  • If enabled, dynamics are changed such that energy is diverted to a species-specific depot and then distributed into the environment reservoirs.
  • Depending on the fill levels of the environment reservoir, interactions may be inhibited or excited …
  • Full store and restore support ... (that was a tricky one)
• Other notable changes:
  • 💥 6b78117d fixes a bug in the attack rate computation
    • 🎉 🎉 🎉 This seems to fix the issue with ever-rising species number!!!
  • 💥 329a30ac changes the order of processes in perform_step
    • ... avoiding to store the system in a weird intermediate state
  • There now is a logger integrated into ODESystem, making debugging easier
  • Added ODESystem::print_info as an action
  • Mutation parameters are outsourced into MutationParams struct

Closes #17 (closed)