Research a spell-checker to use in the extension

[kdoster]

References user story #33

Find a suitable spell checker that can be integrated into the extension

Definition of done:

• [x] Spell checker is compatible with a browser extension
• [x] Spell checker is lightweight
• [x] Spell checker requires little to no use of resources

[torisimon2]

Finished researching LanguageTool for spell checking and added it to the permissions.

[t:120]