(cherry picked from commit f1b7285b)

PR: https://forum.opnsense.org/index.php?topic=10177.0

(cherry picked from commit f00eba92)

Fix for https://github.com/opnsense/plugins/issues/1759

* Restrict download timeout to 5 seconds and 2 retries. Parse only if HTTP response status is 200 OK.
* "Whitelist" (exclude) domains which aren't starting with alphanumeric char causing Unbound not to start.

(cherry picked from commit 0e77afcf)

(cherry picked from commit 53ac1c7e)

(cherry picked from commit b706df5e)

(cherry picked from commit 156be04a)

(cherry picked from commit 8f6a9a66)

(cherry picked from commit e72efeea)

(cherry picked from commit d3ce8111)

PR: https://forum.opnsense.org/index.php?topic=15827.0

(cherry picked from commit 40448f8b)
(cherry picked from commit 74449dba)