Tagging setup key

[davidcarlisle]

• This mostly just replaces testphase=(phase-III,title,math} and \tahpdfsetup{...} by tagging-setup={...}`

• Some warnings that may or may not have been there before

arxiv-3/2401.09965v1-se.log, arxiv-4/1910.06709v2-se.log, bohr/47464-t-se.log

Package tagpdf Warning: Parent-Child 'mtext/mathml' --> 'Link/pdf2'.

links in mathml....

* I broke `tagpdf`

tagpdf/tagpdf-17.log:Runaway argument?
tagpdf/tagpdf.log:Runaway argument?

• and amsldoc all versions but almsldoc-tagged.log

  ! LaTeX Error: Control sequence \g__tag_struct_756_prop already defined.
  ! LaTeX Error: Control sequence \g__tag_struct_kids_756_seq already defined.
  ! Limit controls must follow a math operator.
  <argument> ...s _{A}, \qquad \varliminf \nolimits 
                                                  _{n\to \infty }
  ====>grabbed math=macro:->A_\infty + \pi A_0 \sim \mathbf {A}_{\boldsymbol {\in
  fty }} \boldsymbol {+} \boldsymbol {\pi } \mathbf {A}_{\boldsymbol {0}} \sim \p
  mb {A}_{\pmb {\infty }} \pmb {+}\pmb {\pi } \pmb {A}_{\pmb {0}}
  ! Undefined control sequence.
  <argument> \l_@@_tmpa_box 
  ! Undefined control sequence.
  \pmb@ ...ise \pmbraise@ \box_use:N \l_@@_tmpa_box 
                                                  \kern \dimen@ \mkern .4mu\...
  

(at least the amsldoc ones give same error in main using current code so not affected by this PR)