Flip189 flinksql client features

# What is currently missing?
There is a FLIP189[1] which was accepted however not yet reviewed.
This FLIP among others suggests this set of features
- Line continuation pattern
- Syntax highlighter (`alt-h` to change highlight style)
- Command completion
- Line numbers (`alt-shift-n` to toggle line numbers)
demo for all points mentioned above: https://asciinema.org/a/446247?speed=3.0
- Prompt handler (right and left prompts) demo: https://asciinema.org/a/458191?speed=4.0

# How could this be improved?
I implemented and ported this feature to Flink 1.13.x branch.
So need to update dockerized flink-sql-client from https://github.com/snuyanzin/flink/releases/tag/flip189_1

[1] https://cwiki.apache.org/confluence/display/FLINK/FLIP-189%3A+SQL+Client+Usability+Improvements