Update type declaration with docstrings

[vidartf]

• Adds docstrings to declaration.
• Wraps interface in namespace as recommended by the handbook (https://www.typescriptlang.org/docs/handbook/declaration-files/library-structures.html#preventing-name-conflicts).
• Corrects declaration for setLogTemplate() (it takes a method, not a string).
• Makes typing for click callbacks more explicit.
• Includes version string in declaration.

[vidartf]

Closing due to dead repo.