add LoadText to `nodes_string` to enable wildcard usage

[yoinked-h]

added LoadString and GetRandomLine both of them do what they say LoadString wants MIME text (added it in folder_paths for type checking) GetRandomLine recieves a string, and using torch.randint for seed control, gives a random line (its on CPU and shape 1 so i think its fine)

[LaVie024]

Pardon me, but isn't the random line node a little too similar to the one I made a still-open PR for a bit ago, #8364? This is still useful as a PR though because I did mention that a load string node would be useful for it.

[yoinked-h]

oh. in that case i'll just remove the random line thing then