Squashed 'html/js/datetime/' content from commit 5b3fc61

git-subtree-dir: html/js/datetime
git-subtree-split: 5b3fc61571b126116aafbcd5cb1a7aefb41f9d42
Merge commit 'cc43b3595b596d50b7891ad8cbf0830c5c92f609' as 'html/js/datetime'
Genericise Makefile and do not ignore it
Squashed 'html/js/moment/' content from commit d5ff2cf

git-subtree-dir: html/js/moment
git-subtree-split: d5ff2cfc0000010c37cc5ebe75a5905c943368e4
Merge commit 'a07849b73a0c73c2bcee75d4e1649db239a8b93f' as 'html/js/moment'
Documentation refresh with focus on contribution guidelines