Fix and updated the plugin

[saturninoabril]

Summary

• Updated minimum version to "5.22.0".
• Updated supported languages from AWS Translate.
• Translation is now supported, not only in reference to English but in any combination between source and target languages -- a language pair supported by AWS Translate.
• Updated readme and code owner.
• Updated code setup - circleci setup, make file, eslint, etc.
• Updated the way it store objects. Previously it's modifying the post which is no longer permitted due to its immutability. Now, the store is saved as:

  {
  ...
  plugins-autotranslate: {
  translatedPosts: {
    [post-id]: {/translation object/}
  },
  translations: {
    [translation-id]: {/translation object based on source/target language/}
  },
  userInfo: {/no change/}
  }
  }

Test steps:

1. On initial run, autotranslate plugin is disabled to a user. Post a message and check that “Translate” is not available in post’s dropdown menu
2. See ephemeral help by posting /autotranslate or /autotranslate help. Check text, words or links for any discrepancy.
3. Enable the plugin for current user by /autotranslate on and see that it’s enabled with source: Auto and target: English.
4. Post any message in a different language supported by AWS Translate
   • Check that “Translate” is available in that post. (Note: “Translate” is available to regular post only. Other post like system message should not have that option.)
   • Click “Translate” and see that the post is translated.
   • Click “close” to hide the translated message
5. Try to change different settings (info, source, target, of/off) and see if it works or translates as expected.

[saturninoabril]

(Hmm, diff to go.sum is a bit annoying. Not happening on local. btw, I'll update all at once after dev review)

[saturninoabril]

Thanks Jesse and Ben for the reviews. PR now updated, PTAL.

[saturninoabril]

Thank you for testing Ogi!