feat: add template-lint-migration config

Provides a drop-in replacement for the ember-template-lint `recommended`
preset so consumers can migrate off ember-template-lint onto this plugin
with an equivalent set of rules enabled.

The name makes the migration-from-template-lint intent explicit and avoids
implying that the rule set has been audited for current relevance (it
mirrors upstream). The set is expected to change in the next major via RFC.

Includes:
- Flat config at lib/config/template-lint-migration.js
- Legacy (pre-ESLint 9) config at lib/config-legacy/template-lint-migration.js
- eslint-doc-generator configEmoji entry + regenerated rule docs and README
- plugin-exports test updated
- README section on migrating from ember-template-lint, including how to
  rewrite inline template-lint-disable directives and how to disable a
  rule for an entire .gjs/.gts file via a JS-region eslint-disable

Author: johanrd

.eslint-doc-generatorrc.js

@@ -10,6 +10,7 @@ module.exports = {
   configEmoji: [
     ['recommended-gjs', '![gjs logo](/docs/svgs/gjs.svg)'],
     ['recommended-gts', '![gts logo](/docs/svgs/gts.svg)'],
+    ['template-lint-migration', '📋'],
   ],
   ruleDocSectionInclude: ['Examples'],
   ruleDocTitleFormat: 'prefix-name',