Documentation Example of specify RE patterns when reading csv

[rogerkuou]

We already developed ability to load temporal columns from csv file using RE patterns. However there is no example in the documentation.

We should add example to here: https://tudelftgeodesy.github.io/stmtools/stm_init/

stm = stmtools.from_csv('example.csv', spacetime_pattern= {"^d_": "deformation", "^a_": "amplitude", "^h2ph_": "h2ph"})