Enabled Tarantool performance testing on Gitlab-CI for release/master
branches and "*-perf" named branches. For this purpose 'perf' and
'cleanup' stages were added into Gitlab-CI pipeline.

Performance testing support next benchmarks:

- cbench
- linkbench
- nosqlbench (hash and tree Tarantool run modes)
- sysbench
- tpcc
- ycsb (hash and tree Tarantool run modes)

Benchmarks use scripts from repository:
http://github.com/tarantool/bench-run

Performance testing uses docker images, built with docker files from
bench-run repository:

- perf/ubuntu-bionic:perf_master           -- parent image with
                                              benchmarks only
- perf_tmp/ubuntu-bionic:perf_<commit_SHA> -- child images used for
                                              testing Tarantool sources

@Totktonada: Harness and workloads are to be reviewed.