mixin-backports - Update smarty adapters to v1.0.3

[totten]

Port https://github.com/civicrm/civicrm-core/pull/30281

[totten]

Since this has a fairly low minimum (5.27), and since it's a non-trivial reorg on the mixin, I did a bit more testing than what's in the matrix. e.g.

• Make an extension on 5.27 with a Smarty-based web-page and ensure it works. (This worked fine. 🟢)
• Run the civix test-suites with 5.27 and this patch. (The status-quo is that some civix features don't work on 5.27, so it had pre-existing failures. But the patch didn't make it any worse. 🟡)
• Stress-test smarty-v2@1.0.3 on 5.59. (This is the oldest version where tools/mixin/bin/test-all has coverage for Smarty. This worked fine. 🟢)
• (Incidentally, I also did a s stress-test with using hook_install to render some *.tpls. This didn't work before. In fact, upgrades/22.12.1.up.php and upgrades/23.01.0.up.php already pointed to this. 🟡 )

So overall, 1.0.3 looks to be as good as 1.0.2.

Will merge after 30281.

[totten]

Rebased to include the final revision of smarty@1.0.3. I don't think any of the late changes were version-relevant.