* Adding endpoint in Greenfield to allow server email settings
* Adding related swagger file
* Refactoring EmailSettingsData to be more readable
* Adding server email masking
* Adding tests
* Update BTCPayServer/wwwroot/swagger/v1/swagger.template.serveremail.json
Co-authored-by: d11n <mail@dennisreimann.de>
* Masking smtp server email returned over greenfield api and test
* Retaining password if password mask is used
* Remove magic string *****
* Flatten request for server's settings. Fix bug on shared setting instances
* Remove useless doc
* Simplify code
* Fix Store Email settings page
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Co-authored-by: d11n <mail@dennisreimann.de>
Co-authored-by: nicolas.dorier <nicolas.dorier@gmail.com>
