[2pt] Intro to TT CLI

[patiencedaur]

Epic: Document TT CLI
Related dev page: tarantool/tt#8

Product: Tarantool CLI
Since: 2.10
Audience/target: dev, admin
Root document: TBA
SME: @ Totktonada

What to write

• Why this is needed
• Relation to tarantoolctl and Cartridge CLI. Might involve crosslinking