v0.30.0

For this release i rewrote almost all components to use the new vue composition api.
The rewrite improves the performance and prepares elasticvue for the update to vuejs 3, but might have added some bugs.
Please reach out if you encounter any issues!

• [feat]: can add multiple elasticsearch instances, fixes #35
• [feat]: adds "copy error" button to error messages
• [feat]: can search indices by clicking on their name in the indices table
• [feat]: cleanup tables and remove "sticky header" option. The tables now always use a sticky header