multiple old docs links point to 2.10.x

[gannebamm]

After fixing #83 I realized there are many more links to old docs. Eg:

• [x] Workshops
• [x] Quick Installation Guide
• [x] Full Installation Guide
• [x] Read the Users Guide
• [x] Read the Admins Guide
• [x] Read the developer installation docs for a detailed step by step guide
• [x] Blog >> Geonode 2.10 released >> Installation Guides

[t-book]

thanks @gannebamm we can set 301 at read the docs but we should definitly update the website as well.