move terms to WORK/ directory

Rationale: it is not something meant for site-wide education but is part
of my own notes.
add two tasks
add python syntax notes
update python_syntax
add five task solutions
rename tasks and add three more
Update task_0_5_10.md
Update task_0_5_09.md
add tasks
add task solutions
add task solutions
add task answers
Update task_0_5_15.md
Update README.md
Update README.md
add task solutions
add task solutions
add task solutions
add task solution
add working search engine (task 0.6.6-8)