[Receptionist] updates for the challenge

[Julislz]

Proposed Solution for issue #916

with @sunava
Changes proposed in this pull request:

• the robot shows both guests where the drinks are and detects if their favorite drink is available
• There are passive guests in the background
• Points for small talk (requires to assign guests and host one or two interests and a profession to ask about)
• At the end, only the guests get introduced
• Removed the optional goal 'describing the first guest'.
• Added optional goal picking up a drink
• Added optional goal for finding similarities
• added a procedural guide for quicker and easier understanding of the challenge
• Changed scoresheet accordingly

Updated procedure summarized

Both guests arrive separately. The robot either opens the door for the guest or
waits for them at the starting point. It greets the guest and asks for their name.
The robot then guides the guest to the beverage area, where it asks for their
favorite drink and checks if the drink is available on the table. Optionally, the
robot can pick up the drink. Before reaching the living room, the robot gathers
one additional piece of information about the guest at a freely chosen moment.
After showing the guest the beverage area, the robot escorts them to the living
room and offers a free seat. Once both guests are seated, the robot introduces
them to each other.

Other comments

• I would suggest making it an obligation to log what the robot is saying.
  This makes the process easier for the referee in a noisy arena to check the output quickly after the challenge.

• The passive guests and the host could be spectators if it is not too much effort.

new reachable score for receptionist:
Maximum points without optional goals:
+ 60 pts show guests around
+ 30 lpts ook in the direction of navigation
+ 50 pts identify favorite drink
+ 200 pts offer a free seat to guest
+ 50 pts look at person talking
+ 75 pts introduce both guests
+ 50 pts look at the person talking

= 515 points

with all optional goals:
+ 200 pts door opening
+ 50 pts find similarity
+ 150 pts pick up drink

= 915 points