Add more dimensionality reduction techniques

[vince-lam]

Is your feature request related to a problem? Please describe.

The package currently only applies UMAP dimensionality reduction. More dimensionality reduction techniques, like t-SNE and PCA, could be added to ragxplorer to improve functionality.

Describe the solution you'd like

Add t-SNE and PCA dimensionality reduction techniques to the package by updating the projections.py and ragxplorer.py scripts.

An additional parameter of dim_reduct will be added to the load_pdf and visualize_query methods. This parameter will have a default argument of UMAP and can also take t-SNE and PCA as inputs.

[dan-s-mueller]

Upvote to this feature!