[TASK] Update Form finishers configuration, add mail templates

Classes/Finisher/Forms/FormsFinisher.php

Configuration/MailTemplates/ContactAdmin.php

Configuration/MailTemplates/ContactUser.php

Configuration/TypoScript/setup.ts

Configuration/Yaml/Forms/BaseSetup.yaml

Configuration/Yaml/Forms/CustomFormSetup.yaml

Configuration/Yaml/Forms/FinisherSetupBE.yaml

Configuration/Yaml/Forms/FinisherSetupFE.yaml

Configuration/Yaml/Forms/FormEngineSetup.yaml

Resources/Private/Forms/Partials/Field/Field.html

Resources/Private/Forms/Partials/Field/Required.html

Resources/Private/Forms/Partials/Page.html

Resources/Private/Forms/Partials/Text.html

Resources/Private/Forms/Partials/Textarea.html

Resources/Private/Forms/contactForm.yaml

...urces/Private/Templates/SgMail/ContactAdmin/template.html

Resources/Private/Templates/SgMail/ContactUser/template.html