Z-perl Era Fork - Zperl addon rework for Era fixes

This is a forked then stripped down version of the original Zperl by Resike,

Original version -  https://www.curseforge.com/wow/addons/zperl

It's been through a deep clean to remove all code that was not related to Classic Era and has a tidied up options panel  with non-era options taken away for simplicity and to try improve efficiency a little.

There's also added fixes for broken stuff that came with recent client updates and also some old quirks patched up and ironed out.

Full details:

These are things that were broken before the cleanup and now work:

- Role icons (Tank/Healer/Damage) never showed on player, party, or raid
  frames. All fixed and role icons seem to now work everywhere

- "Hide default raid frames" option wasn't reliably hiding Blizzard's own raid
  frames due to a timing race on login/reload

- Vehicle detection (pet frame), the raid gear-check scan, and the
  auto-maintank-list builder were all silently non-functional due to
  stale version checks blocking real and still/now working Blizzard APIs

- The focus-target frame didn't update at all in four different places
  (Target, TargetTarget, and an ArcaneBar) because the
  event that drives it was never registered

- The "Use Blizzard combo frame" option never actually refreshed the
  combo point display

- ZPerl_CustomHighlight could crash on login for anyone who had never
  opened its options sub-panel, because its settings were only created
  the first time that panel was opened

- The heal status-highlight subsystem (a glow for units already being
  healed) had never seemed to work in Era because of a stale
  version check

Features and code removed -  this never worked on Era, or use spells/classes that don't
exist here:

- Prayer of Mending / Renewing Mist highlight tracking - both spells are
  from Wrath and Mists

- "Predicted heal-over-time" bars (hotPrediction) - a Mists Classic-only
  feature.

- The Shaman "Blizzard Totem Frame" repositioning feature - the
  TotemFrame it targeted doesn't exist in Era

- A couple of features never finished by Resike and never actually wired up to anything yet.

- Six colour-picker options (Runic Power, Insanity, Astral/Lunar Power,
  Maelstrom, Fury, Pain) tied to classes/resources that don't exist on
  Era 

- Dead per-class checkboxes/code for DeathKnight, Monk, Demon Hunter,
  and Evoker scattered across Raid Monitor filters, resource-bar
  checkboxes, combat-rez logic, and debuff-highlight logic - none of
  these are in Era.

- A handful of retail-only UI widgets: extra raid group slots (10-13,
  beyond Classic's 40-player cap logic), pet-happiness options that only
  applied on retail and similar small dead checkboxes.

General Cleanup:

- Removed pretty much every leftover version-check (Retail/TBC/Wrath/Cata/Mists) that
  had no effect on Era, collapsing them down to just the Era  behavior. 

- Removed hundreds of blocks of old commented-out code (abandoned
  attempts, superseded implementations, debug scaffolding) left in the
  addon's source going back to its earliest versions - none of it could
  ever run.

- Consolidated duplicate copies of internal class-list logic that had
  been coppied across multiple files.

- Various small consistency fixes like dangling anchor points or stray and unused
  variables, and mismatched data left over from all of the above.