Make Multiple Connections Share the Main Settings

I have the following parameters in `development.yml`:
```
plugins:
Database:
connections:
rw:
driver: SQLite
database: 'db.sqlite'
dbi_params:
RaiseError: 1
AutoCommit: 1
ReadOnly: 0
TaintIn: 1
TaintOut: 1
RaiseError: 1
PrintError: 1
printWarn: 1
on_connect_do: [ "PRAGMA foreign_keys = ON" ]
log_queries: 1
r:
driver: SQLite
database: 'db.sqlite'
dbi_params:
RaiseError: 1
AutoCommit: 1
ReadOnly: 1
TaintIn: 1
TaintOut: 1
RaiseError: 1
PrintError: 1
printWarn: 1
log_queries: 1
```

I would instead like to share the common parameters, like this:
```
plugins:
Database:
driver: SQLite
database: 'db.sqlite'
dbi_params:
RaiseError: 1
AutoCommit: 1
TaintIn: 1
TaintOut: 1
RaiseError: 1
PrintError: 1
printWarn: 1
log_queries: 1
connections:
rw:
dbi_params:
ReadOnly: 0
on_connect_do: [ "PRAGMA foreign_keys = ON" ]
r:
dbi_params:
ReadOnly: 1
```