added gif to sgd page

See merge request !321

Added extra plots, figures, coding instructions, answer admonitions

See merge request !318

Added dropdown to answer admonitions
fixed full width applet
Added exam information in admonition
Removed some final unnessecary lines
Fixed thebe execute on ridge page
Added links to packages websites
Moved regularization to linear models chapter
Fixed code cells
more stuff.... lost track

Removed code, edited text and thebe-stuff

See merge request !317

ML first draft

See merge request !316