Add functionality to work with new tracker using pages.py

[miguel550]

This PR replaces old functions with pages.py in an attempt to fix all current commands, so far I only tested the load command and it works.

Changes to config.toml to make this work:

• assignment is split into category-task and category-description

To install this version without waiting for the PR to be merged:

pip install git+https://github.com/miguel550/timetracker.git@feat/new-timetracker

To uninstall:

pip uninstall timetracker-cli

[fboaventura]

@miguel550 is this PR ready to merge?

[miguel550]

@fboaventura I would test all the existing functionality first to make sure it's ok to merge, I can test all the remaining functionality tomorrow and then let you know

[miguel550]

Hi @fboaventura, I updated the readme and fixed the show command's table not showing the new table schema. I also tested the load-csv command and it works. The PR is ready for review and for merge.