export: handle multiple contracts

See merge request hito/ositah!4

- No version change but be compliant with PEP

- Dependency requirement on hito_tool >= 23.2

- Remove "export" from the title, leftover from an old version

Allow to configure the authentication provider name displayed in login page

Closes #7

See merge request hito/ositah!2

- Used to be hardcoded to "IJCLab account"

Fixes #7

Initial import of OSITAH from IJCLab

See merge request hito/ositah!1

- number of splits must be passed as a keyword

- Makes easier running ositah from gunicorn where the current directory
can be defined but no option can be easily passed

- Rename ositah.py into main.py to avoid a namespace clash when running
  directly from sources
- Fix imports to reference the ositah module instead of relative directories
- flask and flask-sqlalchemy dependencies locked to version < 2.2 and 3
  respectively (know issues)

- Disable saving of ositah.cfg (site private file containing site-specific credentials)