feat: Add new TableRowPrimaryAction

[kurtdoherty]

Context

• We have table atoms in @reapit/elements/lab/table, but these don't facilitate the level of nuance required by the DS. For example:
  • They are pinned to semantic table elements like td, tr and so on, but we may need the flexibility of using them in a div-based DOM structure instead.
  • They do not provide any solution for the primary row action (which is meant to appear like the row itself is interactive).
  • They do not provide any solution for rendering row header cells.
  • They require column widths to be defined at the cell-level of the table rather than once at the table-level.
• We want to enhance the capability of our table atoms when implementing "official" core versions of them (i.e. the table atoms that will be available via @reapit/elements/core/table.
• The first chunk of this work will be done over a number of PRs and be focused on atoms involved in the table's body:
  • Part 1: Primary action for table rows (this PR)
  • Part 2: Primary data for table body cells
  • Part 3: Double-line layout for cells
  • Part 4: Body cell
  • Part 5: Body row
  • Part 6: Table body

This PR

• Adds TableRowPrimaryAction and TableRowPrimaryActionButton.

note: These components render as an anchor and button respectively, but ones whose "hit area" will expand to fill the bounding box of the closest, relatively-positioned ancestor, which, by default, will be the table row.

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[kurtdoherty]

note: this is the special sauce for the primary action. It's not a fool-proof approach, but it's cheap and will get us moving forward with good a11y and DOM structure.

In particular, it's susceptible to intermediate elements provided by consumers that use relative positioning. Hopefully, this will not prove to be a significant issue, but if it does and we need to work around it, we'll likely reach for anchor positioning (i.e. using CSS anchor positioning to position the ::after pseudo-element w.r.t. to the row as an anchor.

[kurtdoherty]

note: the default font style is the "primary" styled outlined in the design spec. Since this component is for the "primary" action of the row, it should always be used in the row header cell, which is mean to use the medium weight font.