Add MCP4725 DAC Component (#1418)

* Add MCP4725 DAC

* Fix lint

* Fix lint

* Fix lint

* Lint & cleanup

* Lint again

* One more lint

* add test

Co-authored-by: Guillermo Ruffino <glm.net@gmail.com>

esphome/components/mcp4725/mcp4725.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include "esphome/components/output/float_output.h"
+#include "esphome/core/component.h"
+#include "esphome/components/i2c/i2c.h"
+
+static const uint8_t MCP4725_ADDR = 0x60;
+static const uint8_t MCP4725_RES = 12;
+
+namespace esphome {
+namespace mcp4725 {
+class MCP4725 : public Component, public output::FloatOutput, public i2c::I2CDevice {
+ public:
+  void setup() override;
+  void dump_config() override;
+  void write_state(float state) override;
+
+ protected:
+  enum ErrorCode { NONE = 0, COMMUNICATION_FAILED } error_code_{NONE};
+};
+
+}  // namespace mcp4725
+}  // namespace esphome