ref https://linear.app/tryghost/issue/MOM-117
ref https://linear.app/tryghost/issue/MOM-70
- moved current search into new `search-provider` service and updated `search` service to use the provider service internally
- added `search-provider-beta` service
- uses `flexsearch` as the underlying index for each document so we have better indexing and matching compared to the naive exact-match search we had previously
- adds `excerpt` matching for posts and pages
- keeps results output the same as the original search provider
- added `internalLinkingSearchImprovements` labs flag so we can test this internally before reaching our internal linking beta testers
- updated `search` service to switch between providers based on labs flag
closes https://linear.app/tryghost/issue/MOM-174
- bumps @tryghost/koenig-lexical to version that includes a spinner in search popups whilst a search is in progress
ref https://linear.app/tryghost/issue/ENG-1078
- adds required setup for acceptance testing post revisions
- adds happy-path test for listing, previewing, and restoring a post revision
closes https://linear.app/tryghost/issue/MOM-160
- return `undefined` early from `searchLinks` when the underlying task gets cancelled
- bump `@tryghost/koenig-lexical` so it properly handles cancelled search promises
closes https://linear.app/tryghost/issue/MOM-83
- added additional labs flag to allow internal testing prior to private beta release
- bumped Koenig packages containing support for @-link feature
closes https://linear.app/tryghost/issue/MOM-80
- updated internal linking search results items
- removed visibility text from meta data
- added additional icon for paid/specific tier visibility
- added titles to icons
- bumped `@tryghost/koenig-lexical` to include support for meta icon titles
- bumped other Koenig packages due to sub-dependency updates
ref https://linear.app/tryghost/issue/CFR-27
- updated packages to include performance improvement for NQL filter
strings including multiple neq filters for the same resource
- bumped `bookshelf-plugins`
- bumped NQL versions
We identified a performance fix that allows us to combine not equal
(neq) filters for the same resource in a logically-equivalent way that
also has far more performant resulting SQL.
We're effectively automatically combining strings like
'tag:-tag1+tag:-tag2` into 'tag:-[tag1,tag2]'.
