* clean migrate scripts
- refactor migrate:init
- separate admin seed
- separate categories seed
- rework backend README regarding the database
- remove `db:clean` command as its a duplicate of `db:reset`
- remove `__migrate` helper alias
* renamed clean.ts to reset.ts
* set indices & constrains in init function
* fix comment
* disable migrations touching indices
* remove obsolete comment
* always run init on kubernetes
* reset db with or without migrations
* lint fixes
* Refine 'README.md'
* Refine more 'README.md'
* fix lint
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Co-authored-by: Wolfgang Huß <wolle.huss@pjannto.com>
