chore: implement feedback/nits from beta testing

This PR commits some fixes to bugs and improvement suggestions received as feedback from the whirl version of jargons.dev.

Added missing default_branch_only property to fork script, to allow forking of only the project's default branch.
Replaced implementation of javascript:history.back() on editor/new page return navigation wih=th navigation back to /editor page
Updated repo git link in README.md clone repo step to git clone https://github.com/jargons-dev/jargons.dev.git following org transfer
Updated hey.new link to hi.new in CODE_OF_CONDUCT.md support contact and in ISSUE_TEMPLATE/config.yml contact_link url
Added browse words link to homepage under the search trigger
Wrote login page message (Fixes https://github.com/devjargons/jargons.dev/issues/12)
Made jargons editor mobile responsiveness (Related to https://github.com/devjargons/jargons.dev/issues/9)
Implemented temporary workaround for handling deletion of existing reference/branch (Related to #52)
Added jargons.dev logo/sticker to README.md
Addressed some todos
- todo: deprecated the options params in the word-editor script

jargonsdev / jargons.dev