Kibana page layout shared components

[myasonik]

Thinking about improving page layout for Kibana with coming improvements from EUI (to help align Kibana and Solutions) there are several a11y issues around it that could be eliminated through a stricter layout service or series of components.

For a generic page setup:

• Could guarantee main and h1
  • Would be helpful to have a consistent place to jump to ((Accessibility) Skip links to main content #38980) and would solve focus order (number 3 in (Accessibility) SPA routing #42379)
  • We struggle with consistent landmarks (e.g., number 13 (Accessibility) Ingest Node Pipelines UI #71666)
  • We keep playing whackamole with h1 issues ((Accessibility) Multiple apps missing <h1> tag or content for <h1> tag or have nesting defects #61870, (Accessibility) Beats management issues #44544, )

For our common "search box + table" page:

• Would close repeat issues like missing table captions ([ML] (Accessibility) - Machine Learning - Overview page Multiple issues with Tables #51070, (Accessibility) Kibana management issues #44542, (Accessibility) Kibana Stack Monitoring - Tables need better information #42400), and no search results being announced ((Accessibility) Dashboard filters do not notify that page state has changed #62477)
• Could allow for quickly rolling out enhancements ([Accessibility] APM should self-announce and auto-focus search field #28143)

For tab pages:

• Stop allowing links in buttons or vice versa ((Accessibility) Routed tabs cause multiple failures #77828, (Accessibility)Invalid ARIA attribute value for aria-controls on cluster tab of upgrade assistant #29344)

For left hand sub nav:

• Could enhance nav UI {issue missing}

[ryankeairns]

Another think we'll attempt to provide here are top and bottom banners as described in #17298

[elasticmachine]

Pinging @elastic/kibana-design (Team:Kibana-Design)

[cchaos]

@elastic/shared-ux I'd like to evaluate the outstanding items on the list to see if they're still valid and/or close this issue.