[Bugfix] Fix submit buttons/inputs handling

[Telroshan]

The suggested changes should fix the following issues:

• Submit button values are not sent #1506
  => values of clicked submit buttons defining a name/value pair, are now correctly included in the request payload
• hx-post with external submit button excludes the button value #1120
  => Submit buttons/inputs using the form attribute and placed outside a form, are now correctly included in the request payload when clicked
• Missing value of submit button when sending data with ws-send #971 / Missing value of submit button when sending data with ws-send #970 / ws-send does not send submit button name and value #1337
  => form, a and input type="submit" are now processed by htmx not only when the element has chanceOfBeingBoosted. This fixes the issue where you had to put hx-ext on the form itself, otherwise the button's own value wouldn't be in the payload.
  Also, this doesn't seem to do any harm since it doesn't impact the default behaviour when no htmx logic should happen.
  • htmx:beforeProcessNode and htmx:afterProcessNode are going to be dispatched
  • processVerbs won't do anything if the element doesn't declare hx-verb attribute
  • hasExplicitHttpAction being false, nothing happens in the following if either
  • initButtonTracking will be called for any form OR submit button/input that declares the "form" attribute (i.e. outside a form). initButtonTracking is what fixes the issue in the end, as it's going to properly set the form's internalData.lastButtonClicked when clicking a button that it outside that form
• Using the same name attribute on multiple HTML form elements results in only first value being sent #1541
  => values of clicked submit button/input now correctly add to regular input values with the same name, as it does in a standars form

Notes

• Added test cases inspired from all the mentioned issues above
• All tests pass, though let me know if I missed any usecase