Use a more reliable OpenPGP key server by default

I’ve had reliability problems when doing OpenPGP operations in Tails for months (years?). The output of the gpg is pretty unhelpful and, if I understood correctly, the issue is unreliable key servers. For example:

amnesia@amnesia:~$ gpg --recv-keys 0x2BD5824B7F9470E6
gpg: keyserver receive failed: No keyserver available

For some time, I’ve used keys.riseup.net whenever I experience a failed OpenPGP operation and it also always solves it. For example, after the previous error:

amnesia@amnesia:~$ gpg --keyserver keys.riseup.net --recv-keys 0x2BD5824B7F9470E6
gpg: key 0x2BD5824B7F9470E6: 167 signatures not checked due to missing keys
gpg: key 0x2BD5824B7F9470E6: "Thomas Voegtlin (https://electrum.org) <thomasv@electrum.org>" 2 new user IDs
gpg: key 0x2BD5824B7F9470E6: "Thomas Voegtlin (https://electrum.org) <thomasv@electrum.org>" 173 new signatures
gpg: marginals needed: 3  completes needed: 1  trust model: pgp
gpg: depth: 0  valid:   1  signed:  46  trust: 0-, 0q, 0n, 0m, 0f, 1u
gpg: depth: 1  valid:  46  signed: 116  trust: 46-, 0q, 0n, 0m, 0f, 0u
gpg: next trustdb check due at 2019-03-19
gpg: Total number processed: 1
gpg:           new user IDs: 2
gpg:         new signatures: 173

Why don’t we configure keys.riseup.net as the default OpenPGP key server in Tails since it proved to be much more reliable than the current state of things?

Related issues

• Related to #17090 (closed)
• Is duplicate of #12689 (closed)

Original created by @sajolida on 16575 (Redmine)