Add initial docs

[pjanevskiTT]

Fixes #48

Add initial setup on how we want to build docs

This PR is going to be in draft just as a discussion whether this is the way we want to build the docs. Doxygen is used and the format for the functions is same metal uses for host API, compute kernel API etc.

TODOs

• Wait for "New" TTDevice class #40 to know which API to document, is it still going to be tt_device class or tt_umd.h file -> Documenting tt_device
• Open follow up issue to add sphinx tools like in metal and build full page same as Metal docs -> Follow up Add Sphinx docs #59
• Add script to install requirements for doxygen

[broskoTT]

Approved with suggestions

[pjanevskiTT]

Per offline discussion, tt-umd is going to implement doxygen style. Since tt-metal has both table format and doxygen style comments, it can be changed to doxygen style in tt-metal to keep consistency. Multiple things in favour of doxygen style comments that were brought up

• Easier to edit
• clang ruins table format
• Broad audience more familiar with doxygen style

Since it is a bit difficult to say when @brief notation should be used, and we also have quite long function descriptions sometimes, it is not used in any function description

[joelsmithTT]

I did the doc build and am looking at the HTML output -- looks great!