Add support for tags in transactions #76
Description
It should be possible to tag transactions with tags to further categorize them. These can be for things like trips (e.g. London 2020) or to break a category down further.
It should be possible to apply a tag in the transaction list, maybe with a pill control. Also have the ability to remove a tag. When adding a tag, use auto-complete to fill in existing tags but the user can enter a new tag as well.