Rework the introduction pages

[petrapa6]

These three pages need to be reworked such that the reader understands the core features and context in 5 minutes:

• https://ctu-mrs.github.io
• https://ctu-mrs.github.io/docs/introduction/
• https://github.com/ctu-mrs/mrs_uav_system

What's to be included:

• overview images (Tomas: you mean pictures?) and key features
• licensing
• target audience
• quick start tutorial
• high-level architecture diagram and data flow
• list codebase, APIs and libraries
• how does our typical HW setup look like and how to set up it
• basic operation (Tomas: please elaborate)
• where and how to ask for support/questions/troubleshooting
• references, resources

Most of this is inside the documentation itself, but a 5-minute read here must give the reader the basic functionality and context. After reading this summary, the readers MUST know what it's for and how it can be used. It should be visual as much as possible, with the visuals being as straightforward as possible.

[petrapa6]

@klaxalk I won't get any notification if you edit the text description 😄

Take in mind that I drafted the list quickly; it is not set in stone. Also, I don't have the capacity atm to prepare it at once, but I can help with preparing it slowly.

Overview images Yes, pictures or videos serving as the visual presentation. Up for discussion on how to do this. My 2 ideas were

1. a gif collage of 4-6 deployments (outdoor inspection, outdoor racing, outdoor swarming, indoor inspection, indoor inspection multi-robot, indoor vision-based navigation (RoboFly) | all with different robots) or
2. a gif or a diagram showcasing an example dev pipeline: from coding through simulation to real-world.

Basic operation Highlight the robot's autonomy (many people often miss this in our discussions). I.e., describe that we're not a sole autopilot solution and that there is a certain level of autonomy extendable and operable through API/SDK. It should be higher on the list or merged (that's more probable) with some intro text.