…t path for exported files

- **Dockerfile**:
  - Added new file Dockerfile for building Docker image.

- **README.md**:
  - Added section for Docker
  - A usage of application updated to include new parameters `-p` and `--output-path`.

- **app.ts**:
  - Added new variable `outputPath` to define the path of the output file.
  - Updated function for parsing input parameters to include the new parameters `-p` and `--output-path` with defined default value.
  - Updated `console.log` messages to include the new parameters.
  - Updated constant for calling a Chromium browser, including new arguments for launching browser in Docker container.
  - Updated calling `writeJson` and `writeCsv` functions to include the new `outputPath` parameter.

- **write.ts**:
  - Function `writeJson`: Added new parameter `outputPath` to define the path of the output file.
  - Function `writeJson`: Updated constant `outFilename` where base path is defined by `outputPath` variable, not hard-coded anymore.
  - Function `writeCsv`: Added new parameter `outputPath` to define the path of the output file.
  - Function `writeCsv`: Updated constant `outFilename` where base path is defined by `outputPath` variable, not hard-coded anymore.

… review suggestions from PR accepted and implemented

- **Dockerfile**:
  - Fixed obsolete definition of ENVIROMENT variables to correct syntax.
  - Added source link for more information about depebdencies for Puppeteer respectivly Chromium/Chrome in Docker.
  - Dockerfiile moved to `parser` directory.
  - Updated path for `COPY` command.
  - Removed commented code for creataing a new user in Docker. This is not needed for the current implementation.

- **README.md**:
  - Section for Docker updated with new instructions.

- **app.ts**:
  -  Variable `outputPath`: Default value is set to `./out`. Variable is now validated twice.
  -  Variable `outputPath`: Always is checked if path exists. If not, it will be created.
  -  Added source link for more information about calling Chrome/Chromium with `--no-sandbox` flag in Docker while running Puppeteer.