feat: remove the implementation of dev runserver

[Carlos-Muniz]

This PR removes the implementation of tutor dev runserver. It is being removed in favor of using tutor dev start.

This PR should be merged last after each of the following have been merged:

• https://github.com/overhangio/tutor-ecommerce/pull/31
• https://github.com/overhangio/tutor-forum/pull/8
• https://github.com/overhangio/tutor-notes/pull/13
• https://github.com/overhangio/tutor-xqueue/pull/9

Closes https://github.com/overhangio/2u-tutor-adoption/issues/26

[Carlos-Muniz]

@kdmccormick @regisb This is ready for review.

[Carlos-Muniz]

@kdmccormick I've addressed the linting error and added an entry to CHANGELOG.md

[kdmccormick]

Where “TYPE” is either “Bugfix”, “Improvement”, “Feature” or “Security”. You should add an explosion emoji (”💥”) before “[TYPE]” if you are making a breaking change.

This is a breaking change, and I think "Improvement" is the most appropriate type.

[Carlos-Muniz]

@kdmccormick updated with your suggestion 👍

[kdmccormick]

@regisb Carlos is just doing what we asked him to do :) From https://github.com/overhangio/2u-tutor-adoption/issues/26 :

In order to give folks time to stop using runserver, wait until Tutor v14 is released.

But certainly, there's no rush on this. We could definitely wait until Olive or merge this to Nightly, whichever you prefer.

[kdmccormick]

@regisb I've re-opened this PR on top of nightly: https://github.com/overhangio/tutor/pull/718