Add Hue v2 support for the upcoming v2.0.0 release

[amimof]

Adds support for Hue API V2

Features

• Currently V2 work is under the v2/. Folder structure is not final at this point and is sobject to change
• Introduces the new Client struct which is the type used to interact with the Hue API. Instead of using the Bridge type. The Bridge type is now just a regular struct that represents the bridge resource in the V2 API.
• Support for both V1 & V2 API. This is possible because we have 1 client per version. ClientV1 and ClientV2 and in the future ClientVX.
• Huego Clients uses the new CLIPClient which is a general purpose HTTP client. Sort of like a REST client but for Hue briges specifically.
• The CLIPClient uses Request & Response types to communicate with Hue briges through a Client type.
• Users may pass in their own http.Client if they want.

Progress

• light
• scene
• room
• zone
• bridge_home
• grouped_light
• device
• bridge
• device_power
• zigbee_connectivity
• zgp_connectivity
• motion
• temperature
• light_level
• button
• behavior_script
• behavior_instance
• geofence_client
• geolocation
• entertainment_configuration
• entertainment
• homekit

[codecov-commenter]

Codecov Report

Merging #52 (ef38c24) into master (5668ae6) will decrease coverage by 8.73%.
The diff coverage is 35.07%.

@@            Coverage Diff             @@
##           master      #52      +/-   ##
==========================================
- Coverage   73.53%   64.80%   -8.74%     
==========================================
  Files           5       12       +7     
  Lines        1436     1858     +422     
==========================================
+ Hits         1056     1204     +148     
- Misses        210      462     +252     
- Partials      170      192      +22     

Impacted Files	Coverage Δ
v2/room.go	0.00% <0.00%> (ø)
v2/zone.go	0.00% <0.00%> (ø)
v2/clientv2.go	15.78% <15.78%> (ø)
v2/scene.go	28.57% <28.57%> (ø)
v2/light.go	46.15% <46.15%> (ø)
v2/huego.go	52.00% <52.00%> (ø)
v2/client.go	55.26% <55.26%> (ø)

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