Update Delphyne Guide

[francocipollone]

Context

Delphyne guide hasn't been updated for a while and lately many changes related to the ignition migration have taken place.

I've created another document based on the first one as it can be modified. Delphyne Guide 2021

Tasks

On code

• Fixes log argument for the demos when no output filename is passed. e.g. delphyne_gazoo --log:
  Fixes log argument use for demos. #805
  Fixes log argument for demos. delphyne_demos#24
• During ignition migration some files got named with a "2" as suffix. This should be cleaned up: Purges code from old visualizer references. delphyne_gui#455
• Update Readme file Updates README file. #807
• Teleop plugin resize. Resizes teleop plugin. delphyne_gui#458
• Fix delphyne_city demo. Fixes delphyne_city demo. delphyne_demos#26
• Fix delphyne_city demo in focal. Fixes bug in LaneLocationProvider. #813
• Fix delphyne_crash demo: Agent.get_pose() binding failing #808
• Adds smoke tests for all the demos Adds smoke tests for all the demos. delphyne_demos#28
• Fix layout selection when running demos. Fixes layout selection. delphyne_gui#459 Allows layout selection for the demos. delphyne_demos#29
• Fix gui plugin list Visualizer: List of available gui plugins delphyne_gui#460
• Fix text render in the visualizer: visualizer: OriginDisplay causes bad text render on other plugins delphyne_gui#469

On document

• Correct naming in the entire document: e.g delphyne-replay --> delphyne_replay
• Update pictures using ign-gui3 based visualizer when necessary.
• Update Build & Installation section which also implies a modification at delphyne's README that is outdated.
• Update Style Checking & Formatting section: cpplint isn't being used.
• Verify code snippets related to Python layer.
• Verify info about Agent Framework.
• Adds an example on how to use the Agent.
• Adds info about BehaviorTree machinery
• Update On the RoadMap section(?)
• Update collision detection snippet code as it doesn't work.
• Update info about PlaybackWidget as it was replaced by PlaybackPlugin.
• Update Manipulating the Time Stream section.
• Plot widget section: It wasn't migrated to ign-gui3. Plot plugin delphyne_gui#456
• Add info about the teleop plugin
• Add info about the TopicStats plugin
• Add info about the TopicViewer plugin
• Update info about Scene Tree Widget: This plugin was reimplemented as ign-gui3 didn't migrate it from ign-gui0.
• Update Displays Widget section as many were reimplemented.
• Adds info about gui configuration save/load.

Bonus

• This guide probably should be added to maliput_documentation/ delphyne_documentation(if exists in the future)