Add cache library

[lvjr]

Sometimes TikZ is rather slow, so it provides external library to speed it up. Maybe tabularray could add an cache library some day to make it run faster in the second run.

In fact, tabularray need to measure every cell at least once to get correct dimensions before building a table. When there are X columns, it has to measure each cell for the second time; and when there are multicolumn cells, it has to measure each cell for the third time. If it can save the column widths to the .aux file or a .tblr file, then it might only need to measure each cell once in subsequent runs.