SFTP. Update component to new sailor version / use new logger functionality / dockerize

DoD Development:

[x] use new logger
[x] component should be dockerised, add: "buildType":"docker" line into component.json
[x] sailor version is changed from 2.2.0 to 2.5.4
[x] CHANGELOG.md is updated QA:
[x] Smoke test is finished
[ ] Regression testing is finished (optional)
[ ] Support is asked to deploy to the production stage (app.elastic.io) and/or another required stage
[ ] Component is actually deployed to the production stage (app.elastic.io) and/or another required stage
[ ] Smoke after deploying to the production stage

elasticio / sftp-component