Create the Text bindings

[LSViana]

Implement the bindings for the Text struct based on the exposed bindings.

• [x] Create class definition
• [x] ytext
• [x] ytext_len
• [x] ytext_string
• [x] ytext_insert
• [x] ytext_format
• [x] ytext_chunks
• [x] ytext_insert_embed
• [x] ytext_remove_range
• [x] ytext_observe
• [x] ytext_unobserve
• [x] ytext_event_target
• [x] ytext_event_path
• [x] ytext_event_delta
• [x] ytext_delta_destroy
• [x] ytext_delta_destroy
• [x] yobserve_deep
• [x] yunobserve_deep

For each bound method, the implementation and unit tests must be written.

[LSViana]

All the bindings have been finished. Waiting on the team's comments about how to properly test ytext_event_path before merging this PR.

[LSViana]

I'm going ahead and merging this PR now. Some tests might be added later based on the team's response about how to properly test the event path feature of YText events.