[new]: `export_to_bigtable(project, table, key, value)`

[unytics]

Check the idea has not already been suggested

• [X] I could not find my idea in existing issues

Edit the title above with self-explanatory function name and argument names

• [X] The function name and the argument names I entered in the title above seems self explanatory to me.

BigFunction Description as it would appear in the documentation

Examples of (arguments, expected output) as they would appear in the documentation