Loopback Connector Disregards Property Name

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## Description / Steps to reproduce / Feature proposal
The @ property decorator has a name property which should specify the column name in the database in case it does not match with the field name in your model. However, the code in loopback-connector/sql.js does not utilize this metada so you only get the field name as it's defined in your model. In my case, I am using DB2 and this causes issues because the generated SQL select statement uses double-quotes around each field signify to DB2 that the field name matches exactly with what is specified in the DB (i.e. case sensitive).

To Reproduce:
Create a DB2 database w

1. ith a table "DRIVER" that contains field "DRIVER_ID".
2. Setup a basic Loopback4 project like the Todo Tutorial (replacing instances of Todo with Driver) but use a DB2 based datasource.
3. Create the Model like the following:

```typescript
@model({
name: 'DRIVER', // This corrects the case-sensitive issue at the Table level.
}
})
export class Driver extends Entity {
@property({
name: 'DRIVER_ID', // This is ignored by field mapping functions.
type: 'number',
id: true,
})
fooId?: number;
```

4. Use VS Code to start the server in Debug and issue a GET against drivers
5. In the sql.js --> buildColumnNames note that the name is 'fooId' instead of 'DRIVER_ID'
6. Continue execution, you will receive an SQL0206N error from DB2: "fooId" is not valid in the context where it used.

## Current Behavior
sql.js simply uses the field names as the DB column names.

## Expected Behavior
sql.js should map to the @ property 'name' property to determine the correct column names.

## Connectors to fix

- [x] SQL connectors - done by strongloop/loopback-connector#142
- [ ] MongoDB https://github.com/strongloop/loopback-connector-mongodb
- [ ] CouchDB2 https://github.com/strongloop/loopback-connector-couchdb2
- [ ] Cloudant https://github.com/strongloop/loopback-connector-cloudant (may depend on couchdb2)
- [ ] Cassandra https://github.com/strongloop/loopback-connector-cassandra

Start in loopback-connector/sql.js at buildColumnNames and compare its field-name handling with the property name metadata shown in the reproduction. Check the referenced SQL connector change before modifying this issue. Done means generated SELECT columns use DRIVER_ID for the fooId property and the DB2 reproduction no longer raises SQL0206N.

Written by the indexing model from the issue text.