ci(vale): add a pr check workflow for vale

[StaticRocket]

• ci(vale): add a pr check workflow for vale

  Add a pull request driven workflow for vale. This is based on the upstream
  action documentation [1], but limit it to changed files only to keep feedback
  snappy.

  This currently uses a fork I made of the upstream action that's capable of
  using the locally installed version of vale. This allows us to use our
  container as is, which is faster than reinstalling tools and makes issues more
  easily reproducible. This is only required until the upstream PR is accepted
  [2].

  This does not enable this action as a blocking check just yet. There is still
  an upstream bug that makes all feedback throw a failure, which is a little too
  aggressive right now. Still need to tune things a bit.

  [1] https://github.com/errata-ai/vale-action
  [2] feat: allow use of local version of vale errata-ai/vale-action#149

  Signed-off-by: Randolph Sapp rs@ti.com

• ci(vale): switch style dir, add vocab

  Use the recommended config directories for the official workflow [1]. Add a
  vocab accept list for some common terms I see currently being flagged. This
  will need to be extended.

  [1]
  https://github.com/errata-ai/vale-action?tab=readme-ov-file#repository-structure

  Signed-off-by: Randolph Sapp rs@ti.com

• ci(docker): add vale to the main docker image

  Add vale to the main image so we can reuse this container for vale's ci
  workflow to save some time.

  Signed-off-by: Randolph Sapp rs@ti.com

[cshilwant]

@praneethbajjuri / @VeeruPrudhvi / @uditkumarti for final ACK & integration