Webcode-tk

Adding some functionality to get all permutations of selectors based on tag name, id, and class selectors.

- `get_possible_selectors_by_tag(file_path: str, tag: str)`
- `add_if_not_in(my_list: list, item: str)`

TODO:
* add potential descendant and other advanced selectors (that will be a different function)

Enhancing link selectors and applying inheritance to determine colors applied when appropriate.

TODO: enhance all CSS styles to examine inheritance when possible.

We can now get link color data for projects.

We can now search for properties to see if a property has been set on a selector, and we can get the value of a selector from a declaration block.

Adding two functions to html_tools:

- `get_style_attribute_data()` - gets data on whether an html document uses the style attribute or not - including the value set by the style attribute for each tag that uses it.
- `has_style_attribute_data()` - let's us know if there is a style attribute or not.

I've added and adjusted all functions related to color contrast and global colors to make test a website a little easier.