os-caddy add possibility to configure propagation_timeout and propagation_delay

[andreasziegl]

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Is your feature request related to a problem? Please describe.

For some DNS providers it is required to configure the propagation timeout and delay e.g. Netcup. setting the timeout to -1 is not sufficient, also the delay is required.

Describe the solution you'd like
Possibility to set the values in the GUI

[Monviech]

Adding this is very simple, maybe somebody wants to give it a shot?