Allow non-unique story titles

[ferguskelly4]

Only allowing 30 chars or story titles (or tags) and forcing them to be unique makes coming up with new titles for similar stories or for an update to an older story difficult. The story integer is already unique, why a second?

[levinotik]

Could be done with a migration and fixing whatever else is currently depending on unique story titles (for example looking up stories from URL currently ignores the id and looks only at the name).

The uniqueness constraint is defined here https://github.com/grasswire/Grasswire-Platform/blob/master/common/src/main/scala/com/grasswire/common/db/tables/ContentTables.scala#L355