API/CLI - add ability to produce machine-readable trace/output

[SubPointSupport]

metapack trace and logs should also be available in JSON format.

API should have additional trace service for that, and CLI should have additional flag to indicate machine-readable trace mode. Flag as the followig will do:

--output json

Such feature is needed by 3rd part API integrations, CLI and desktop client so that they would be able to capture trace in platform/API independent way.

[SubPointSupport]

Implemented. Use --output json to get the following trace:

{"Level":"Information","TimeStamp":"\/Date(1490617249565)\/","Message":"Metapack client v1.0.17082.1051"}
{"Level":"Information","TimeStamp":"\/Date(1490617249581)\/","Message":"Working directory: [E:\\MetaPack\\MetaPack.Client.Console\\bin\\Debug]"}
{"Level":"Information","TimeStamp":"\/Date(1490617249640)\/","Message":"Using O365 runtime and SharePointOnlineCredentials"}
{"Level":"Information","TimeStamp":"\/Date(1490617249648)\/","Message":"Fetching the latest package [DefinitelyPacked.ArvoSys.spf-newitemcallout]"}
{"Level":"Information","TimeStamp":"\/Date(1490617252923)\/","Message":"Found package [DefinitelyPacked.ArvoSys.spf-newitemcallout] version [1.0.0]."}
{"Level":"Information","TimeStamp":"\/Date(1490617252924)\/","Message":"Installing package to SharePoint web site..."}
{"Level":"Information","TimeStamp":"\/Date(1490617256120)\/","Message":"Force flag is true. Looking for existing package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617257456)\/","Message":"Package [DefinitelyPacked.ArvoSys.spf-newitemcallout] version [1.0.0] already exists. Uninstalling..."}
{"Level":"Information","TimeStamp":"\/Date(1490617270972)\/","Message":"NuGet package installation started"}
{"Level":"Information","TimeStamp":"\/Date(1490617270973)\/","Message":"Package [DefinitelyPacked.ArvoSys.spf-newitemcallout] version [1.0.0]"}
{"Level":"Information","TimeStamp":"\/Date(1490617270977)\/","Message":"Resolving solution tool package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617271006)\/","Message":"Resolved solution tool package [MetaPack.SPMeta2] version:[]"}
{"Level":"Information","TimeStamp":"\/Date(1490617271007)\/","Message":"Installing solution tool package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617271024)\/","Message":"Resolving additional tooling for tool package [MetaPack.SPMeta2]"}
{"Level":"Information","TimeStamp":"\/Date(1490617271426)\/","Message":"No additional tools were found"}
{"Level":"Information","TimeStamp":"\/Date(1490617271427)\/","Message":"Resolving solution packaging implemetation"}
{"Level":"Information","TimeStamp":"\/Date(1490617271803)\/","Message":"Resolved solution tool implemetation:[MetaPack.SPMeta2.Services.SPMeta2SolutionPackageService]"}
{"Level":"Information","TimeStamp":"\/Date(1490617271804)\/","Message":"Resolving solution deployment implemetation"}
{"Level":"Information","TimeStamp":"\/Date(1490617272179)\/","Message":"Resolved solution deployment implemetation:[MetaPack.SPMeta2.Services.SPMeta2SolutionPackageDeploymentService]"}
{"Level":"Information","TimeStamp":"\/Date(1490617272180)\/","Message":"Unpacking solution package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617272511)\/","Message":"Extracting additional tools from solutuion package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617272513)\/","Message":"Current AppDomain.Id:[5]."}
{"Level":"Information","TimeStamp":"\/Date(1490617272515)\/","Message":"Packaging service impl:[MetaPack.SPMeta2.Services.SPMeta2SolutionPackageService]."}
{"Level":"Information","TimeStamp":"\/Date(1490617272517)\/","Message":"Deployment service impl:[MetaPack.SPMeta2.Services.SPMeta2SolutionPackageDeploymentService]."}
{"Level":"Information","TimeStamp":"\/Date(1490617272689)\/","Message":"Creating packaging service implementation..."}
{"Level":"Information","TimeStamp":"\/Date(1490617272690)\/","Message":"Creating deployment service implementation..."}
{"Level":"Information","TimeStamp":"\/Date(1490617272691)\/","Message":"Unpacking package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617273635)\/","Message":"Succesfully unpacked package."}
{"Level":"Information","TimeStamp":"\/Date(1490617273638)\/","Message":"Checking additional tools for unpacked package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617273638)\/","Message":"Calling SolutionPackageDeploymentService.GetAdditionalToolPackages()..."}
{"Level":"Information","TimeStamp":"\/Date(1490617273643)\/","Message":"Deploying package..."}
{"Level":"Information","TimeStamp":"\/Date(1490617273645)\/","Message":"Solution package requires [4] additional tools"}
{"Level":"Information","TimeStamp":"\/Date(1490617273646)\/","Message":"    Installing additional tool [SPMeta2.CSOM.Foundation-v16] version []"}
{"Level":"Information","TimeStamp":"\/Date(1490617274171)\/","Message":"    Installing additional tool [Microsoft.SharePointOnline.CSOM] version []"}
{"Level":"Information","TimeStamp":"\/Date(1490617274176)\/","Message":"    Installing additional tool [Microsoft.SharePointOnline.CSOM] version []"}
{"Level":"Information","TimeStamp":"\/Date(1490617274182)\/","Message":"    Installing additional tool [SPMeta2.CSOM.Standard-v16] version []"}
{"Level":"Information","TimeStamp":"\/Date(1490617274244)\/","Message":"Detected [4] assemblies to be loaded"}