transmission: add ca_bundle support with procd-ujail

transmission: add ca_bundle support with procd-ujail

With procd-ujail enabled, it is not possible to use HTTPS URLs, for
example when either for downloading torrent files or blocklists. The
followig example occurs when downloading a URL from the "Upload Torrent
Files" dialogue box:

Error adding
"https://releases.ubuntu.com/21.10/ubuntu-21.10-desktop-amd64.iso.torrent":
gotMetadataFromURL: http error 0: No Response

syslog will also hint that no CA_BUNDLE is being used:

transmission-daemon[6683]: [2021-12-30 20:01:30.990] web will verify
tracker certs using envvar CURL_CA_BUNDLE: none (web.c:455)

This patch rectifies this issue by adding a ca_bundle configurable,
enabled by default. This explicitly fixes the ca_bundle file location
to /etc/ssl/certs/ca-certificates.crt and adds this file to the procd
jail. On subsequent testing, HTTPS URL download functionality is
restored.

Signed-off-by: Matthew Hagan <mnhagan88@gmail.com>