tt CLI (2.10): add completion support for `fish` shell

[xuniq]

Product: tt CLI
Since: tt 2.10.0
Dev ticket: tarantool/tt@354a17a
Root document: https://www.tarantool.io/en/doc/latest/tooling/tt_cli/completion/

SME: @ oleg-jukovec @ dmyger

Details

Added support for autocomplete when working interactively in the console
for the fish shell. Use tab to display hints of available
command entry sequence.

Usage Example:

eval "$(tt completion fish)"

Closes #TNTP-2893