Mara-app

- add option to shorten cli commands (48)

- upgrade to bootstrap 4.6 (from alpha 4)<br>
*Caution:* Some CSS classes changed between Boostram Alpha 4 and 4.6. You might need to upgrade other mara packages as well, e.g. mara-pipelines and mara-app.
- do not modify the click command name when it is a MultiCommand 42 (44)

- adding .scripts files into the PyPI package

**required changes**
- If you use the Makefile/.scripts logic, you need to copy once the file `mara_app/.scripts/init.mk` into your scripts folder.<br/>
This can be done by executing once `cp packages/mara-app/mara_app/.scripts/init.mk .scripts/mara-app/init.mk` in your shell.

- fix missing static files in pip package (32)

- Improve loading speed of navigation entries

- Always upgrade packages used in makefile to latest version (29)
- Add target for deleting all pip installed code