Add price per weight ratio

[UnknownSilicon]

Adds a field on the bean information page showing the price per weight ratio of the bean.
Adds a setting to toggle price per weight ratio field.

[CLAassistant]

All committers have signed the CLA.

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[graphefruit]

Hey @UnknownSilicon,
thanks for the PR and the workload you've done with this.

After there where some PR's lately I've written a new ticket to help everyone before creating a new PR for Beanconqueror: #723

I'm not 100% convinced about the concept made with this code changes.
The calculcation to gram or I'd rather think about 1kg is more or less a function not a parameter which needs to be customized, also it makes it more hard to understand for the users.

I've already recieved some requests to maybe support so show like how much would the bag cost with 1kg, so I'd more take some more reference to this case.
If 1000grams would be added, there wouldn't be any calculcation needed anyway.

The code doesn't handle when you didn't enter any costs but the grams.

So to reduce customization and new labels for this use case:
What does speak against to add it to the <ion-text>{{bean?.cost}}</ion-text> cost field, and add behind in (X/KG) e.g.?
Best
Lars