Docs Modernization and Glyphs major update

[mtripnaux]

I used Jinja2 for HTML templating, and the documentation code is now located under /templates.
Two python scripts are available under /source. The first one builds the CSS standalone file from the SVG folder and creates a JSON file to describe the icons, their names and paths. These two files are built in the /dist directory. The second script builds the documentation from templates, taking in account the JSON file (displays the glyph count, lists the CSS classes, etc).

The github pages integration is now using the Github Actions framework, with an automated build pipeline that builds the entire /dist folder from sources at each pushed commit. The /dist is then served in the repo's Pages.

5 SVGs were added :

• source/SVG/aptamer.svg
• source/SVG/inert-dna-spacer.svg
• source/SVG/origin-of-transfer.svg
• source/SVG/stop-codon.svg
• source/SVG/poly-a-site.svg

14 SVGs were modified to look better on screen :

• source/SVG/engineered-region.svg
• source/SVG/five-prime-sticky-restriction-site.svg
• source/SVG/three-prime-sticky-restriction-site.svg
• source/SVG/five-prime-overhang.svg
• source/SVG/three-prime-overhang.svg
• source/SVG/user-defined.svg
• source/SVG/origin-of-replication.svg
• source/SVG/insulator.svg
• source/SVG/operator.svg
• source/SVG/assembly-scar.svg
• source/SVG/blunt-restriction-site.svg
• source/SVG/cds.svg