CommandLine plumbing infrastructure

[ArinGhazarian]

Related to #639

This is all the required infrastructure changes in form of some extension method to do the plumbing for the new CommandLine. Here is a sample branch that applies these changes to bbs2gh. I went ahead and simplified it even more by creating an extension to add all commands to the rootCommand. Here is how it's supposed to be used:

public static async Task<int> Main(string[] args) // note that Main now returns a Task<int> instead of Task
{
    Logger.LogDebug("Execution Started");
 
    var serviceCollection = new ServiceCollection();
    ... // service registrations
    var serviceProvider = serviceCollection.BuildServiceProvider();

    var rootCommand = new RootCommand("Automate end-to-end Bitbucket Server to GitHub migrations.")
          .AddCommands(serviceProvider);

    ...
}

• [x] Did you write/update appropriate tests
• [x] Release notes updated (if appropriate)
• [x] Appropriate logging output
• [x] Issue linked
• [x] Docs updated (or issue created)

[github-actions[bot]]

Unit Test Results

0 tests   0 :heavy_check_mark:  0s :stopwatch: 0 suites  0 :zzz: 0 files    0 :x:

Results for commit bdd4a62b.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Integration Test Results

4 tests  ±0   4 :heavy_check_mark: ±0   14m 46s :stopwatch: - 1m 43s 1 suites ±0   0 :zzz: ±0  1 files   ±0   0 :x: ±0 

Results for commit ecc9bdf0. ± Comparison against base commit c752c8ed.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Package	Line Rate	Branch Rate	Complexity	Health
Octoshift	89%	75%	854	✔
bbs2gh	73%	65%	261	➖
ado2gh	88%	83%	578	✔
gei	81%	87%	429	✔
Summary	85% (5378 / 6304)	78% (1162 / 1490)	2122	✔