Increase run description field height and max length

[didmar]

Is your feature request related to a problem? Please describe.

In the run settings modal, the description field of the run is too small for what is required in the guidelines:

a short (less than 1 page) description of how the rest of your story/run might play out. (E.g., some notes on your setting, characters you might introduce later, and where the plot might go.)

Describe the solution you'd like

• [x] Increase the maximum length of the description accordingly, such as 1000 words max.
• [ ] Increase the description field height such that a ~500 words description is entirely visible (without scrolling).
• [ ] Update the placeholder with the quote above.
• [ ] Also, the modal should be scrollable, otherwise, some of the settings won't be visible on small screens.

[didmar]

Increased max length with 5518ce99800a241d91c24fac2c0fc44f7cb5fef3