Modify the git commit guide to be clearer, specifically asking to link
GitHub issues with every commit. Also update the pull request template
with the line "Fixes #issue-number" so that every PR will close an issue
when it is merged.
* attempts to improve .github contents
* more changes
* restructure nature of issue
remove redundant information in first block comment
(it's already mentioned above each section's heading)
* delete unused files, move webpack configs to their own directory
* start of improved developer documentation, moving everything to developer_docs/ directory
* documentation updates
