Rider plugin release chores

[Domonion]

Description

Before releasing plugin on Jetbrains Plugin marketplace several things should be done in advace:

• Rider alpha version - Add basic Rider plugin structure #1120 moved to Rider plugin #1463 and VSharp process start fix #1484
• Rider plugin build workflow - Rider plugin workflow #1462 and Rider plugin #1463
• plugin xml, change notes, gifs, landing page - Rider plugin text and landing #1487
• utbot.org` C# playground and demos - @VictoriaFomina

This is parent issue for everything related to UtBot C# plugin

[Domonion]

Closed as released in 2022.12