Change page so Enigmail is replaced with native Thunderbird OpenPGP encryption

[missytake]

https://riseup.net/en/security/message-security/openpgp/enigmail seems to be pretty outdated, in fact it hasn't been updated since 2019. It still recommends enigmail as a plugin for Thunderbird, which is not compatible with the latest Thunderbird releases anymore.

Thunderbird offers native openPGP encryption now, and while it isn't ideal and Enigmail was better in many ways, that's the go-to way of using openPGP with Thunderbird at the moment. So it would be nice if there was a straight-forward site on this, recommending some reasonable best-practices as well and explaining the weird quirks of the Thunderbird implementation.

The changes need to be in this directory, it would probably would make sense to rename it or something: https://github.com/riseupnet/riseup_help/tree/no-masters/pages/security/message-security/openpgp/enigmail

Thanks to you if you care about it to change this! <3