Feature request: define amount by member type in new and renewal form

[daraelmin]

Feature Request

[Short description]

Use case

Send a member a link to renew his subscription. If the amount has changed the amount should be the new one not the latest.
If the member change his type, the new amount should be set to for this type.

Suggested implementation

#17194 NEW option to select membership type on the online payment page for membership subscription or renewal

was canceled by commit

ce1a257 Fix remove a setup that should not exists. Info is already into a table

So I suggest to add add a new field "amount" in llx_adherent_type as the info doesn't really exist in table llx_subscription.
htdocs/install/mysql/tables/llx_adherent_type.sql

Trying to retrieve the amount fron llx_subscription won't always work as the amount from subscription is a record from the past. How should we process when we offer new adherent type ? Or when the subscription amount is changed ?
htdocs/install/mysql/tables/llx_asubscription.sql