Finish first pass of type annotations for `lib` + other small changes.

[mattmccutchen]

This gets most files in lib to typed: strict. I also looked briefly at the output of Sorbet's "highlight untyped code" feature and made a few more obvious fixes.

Notable large changes:

• Replace untyped "options" hashes with keyword arguments (for Config#initialize) or T::Struct subclasses (for Mirror::new_from_options and commands). This required adding barebones support for T::Struct to the fake Sorbet runtime.

• Command arguments were passed through Command::run as an untyped *args. We want to have different argument types for each command, but we want to continue to share the wrapper code in Command::run across all commands. So have the commands take their arguments in initialize instead of run and let the caller call new on the desired command class directly instead of having Command::run do it.

Notable small changes:

• Add false default for some command-line options so we can annotate the corresponding variables as non-nilable.

• Now that we don't want clear_remote taking an untyped options hash, it seems clearest to just duplicate the @options.keep conditional at each caller that has such an option (Add doesn't, for whatever reason).

• Remove options from the Status command because the CLI never passed them anyway.

• To resolve a type error that showed up in Mirror::new_from_options when we annotated the options, clean up extract_path_from_url so that it never returns nil. Take advantage of String#delete_suffix, which requires Ruby >= 2.5.0, so bump the minimum Ruby version in the gemspec. (I haven't tested that everything else works on Ruby 2.5.0; we currently don't have a good process to ensure the minimum is set correctly.)

• Fix Push#config_mode that was defined in the wrong place, and add a test.

---

The tests pass on my Linux and Windows systems.

[realityforge]

Still on my radar ... although I may not get a chance to look at it until tomorrow or Saturday ;-)

[realityforge]

I did need to make one change to this PR to get it to work for me. I suspect it is because I am using an older version (2.7.2) of ruby?

Other than that - good work!

$ git diff
diff --git a/lib/braid/sorbet/fake_runtime.rb b/lib/braid/sorbet/fake_runtime.rb
index 387768c..90452df 100644
--- a/lib/braid/sorbet/fake_runtime.rb
+++ b/lib/braid/sorbet/fake_runtime.rb
@@ -88,7 +88,7 @@ module Braid
         define_method(prop_name) {
           @attrs[prop_name]
         }
-        define_method(prop_name.name + '=') { |new_value|
+        define_method(:"#{prop_name}=") { |new_value|
           @attrs[prop_name] = new_value
         }
       end