disable Gravatar by default

[luckow]

To be GDPR compliant, we should disable Gravatar in the default configuration. Since sogo.conf is located in the read-only part of the file system (/run/sogo.conf), this is a task for the app packager

Param is

SOGoGravatarEnabled = YES;

and it must be switched to = NO;

[nebulon]

@luckow the upstream default is YES if unset, so we should stick with the defaults for everything not Cloudron related. However the package should allow to change this. Will see how that can be done.

[girish]

@luckow I have updated the package now.

[luckow]

@girish wohoo. Also great news for @gobenizzle (related to https://forum.cloudron.io/topic/4407/sogo-conf-missing?_=1622375435623)