xF2 Add-on Thread & Post BB Code for XF2 2.4.0

• Require XenForo 2.2+
• Require php 7.2+
• php 8.2 compatibility fix
• Minor performance tweak to only invoke the thread/post id tracking on those tags instead of every tag parsed

• Require XenForo 2.1+
• Require php 7+
• Confirm XF2.2+ support
• Fix that [post] bb-code could leak thread titles for threads a user should not be able to see.

• Require XF2.1+
• Reduce N+1 like query behaviour when loading forums to check thread visibility

• Performance tweaks when used a large number of times on a single page

• Add an add-on icon

• Initial XF2.1 compatibility update

• Fix a memory leak when running from a long running process (effects User Essential's mention tracking rebuild)

• Essentially rewrite link generation
  • From @Sim's [thread] and [post] BBCode add-on, copy the behaviour for email based rendering.
  • Use full links, not relative links.
  • When linking to a viewable post, use a thread-page-#post structure to allow previewing which page the link is one.
  • Use correct css for attributes.
• Note; this add-on only supports pulling a post/thread id from the option value

• Tweak execution order of class extensions/template modifications/etc to provide predictable ordering
• Add LICENCE and README.MD to redistributable.