Move tutorials out of examples folder

[btjanaka]

Description

Since there are far more tutorials than examples, it does not make sense to keep them under the examples directory. This PR moves them to a separate top-level directory which is more visible to users and fixes various filepath issues.

TODO

Questions

Status

• [x] I have read the guidelines in CONTRIBUTING.md
• [x] I have formatted my code using yapf
• [x] I have tested my code by running pytest
• [x] I have linted my code with pylint
• [x] I have added a one-line description of my change to the changelog in HISTORY.md
• [x] This PR is ready to go

[btjanaka]

Errors are due to filepath changes. Everything should work once merged.