Get rid of d3-bootstrap popovers and remake them cleanly

[boogheta]

cf https://github.com/regardscitoyens/the-law-factory/pull/165/commits/e50fa5078222b5bf9ca3de21e3634cb57e1b0e83#diff-dd8271e7127bd66edbcb8b4521d96d5eL501

Remember to ensure that popover on articles appear on top instead of bottom when on bottom of page (#202)