Extend documentation with additional examples

[uniqueg]

Provide tutorials and examples for using TESK with cwl-tes, Snakemake and Nextflow clients.

[uniqueg]

Requested by the Czech ELIXIR node, see here: https://docs.google.com/spreadsheets/d/1vBFhBQ-nFqhSL5dLjQfOWO6x9BzmV9x6l18p9GYRZdQ/edit#gid=0

Contacts: @xhejtman & @viktoriaas