Add Trajectory Visualizer v.20

[bhavul]

Many upgrades - categorisation, search, filters, raw logs available, slurm logs dynamically available if present.

1. tasks are categorised in side panel
2. filters available for model and task type
3. raw logs also present in a collapsible container to check
4. every trajectory has a proper URL, so you can share direct URL with someone
5. search box — where you can search any substring of the run name.
6. Slurm logs available if slurm output and error files were present in the trajectory DIR. Otherwise they're skipped.
7. Different trajectories have different URLs now, so you can easily share a particular trajectory link with someone.

Tested via : streamlit run demo/trajectory_visualizer.py -- --trajectory_dir ./trajectories/bhavul/ on devserver.

[deepakn97]

The thought process is rendered outside the block. Should fix this.

[deepakn97]

The test command and the files changed don't match. It is mentioned that the changes were tested using demo/trajectory_visualizer.py, however the changes are in demo/demo.py.
These two files serve different purposes. Demo is meant to be a automated demo where the users don't have to click through the next step and previous step buttons and should be used when making a demo video etc. Whereas trajectory visualizer is supposed to be used for stepping through the actions and thought process of the agent by a user.

Not sure what is the intended change here.