Create Hanna BL121 Pool Controller integration

[Zuntara]

Integrate the Hanna Instruments BL121 Pool controller with pentair code as a module.

PR ongoing : #4

• This has as goal that the injection of Cl and Ph can be stopped when the Pentair pump has a problem
• The owner can be notified when the Cl, Ph or Temp levels are off
• The owner can be notified when the Cl or Ph tank level is low