Add Ability to Broadcast to Client Sockets

[shellscape]

• This is a bugfix
• This is a new feature
• This is a code refactor
• This is a test update
• This is a typo fix
• This is a metadata update

For Bugs and Features; did you add new tests?

Yes

Motivation / Use-Case

For certain recipes, such as watching files or implementing progress feedback, the socket server needs the ability to accept and broadcast a message to all other client sockets. For instance, to reload the window.

This PR adds that ability, and adds a new socket handler in the client, window-reload which serves only to reload the page without any special logic.

Breaking Changes

None

Additional Info

[codecov]

Codecov Report

Merging #39 into master will increase coverage by 0.64%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master      #39      +/-   ##
==========================================
+ Coverage   85.43%   86.07%   +0.64%     
==========================================
  Files           3        3              
  Lines         151      158       +7     
==========================================
+ Hits          129      136       +7     
  Misses         22       22

Impacted Files	Coverage Δ
index.js	87.95% <100%> (+1.1%)	⬆️

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