Sanity checks for Kea 1.8.1 rc1

We are now at step SANITY CHECKS of Kea 1.8.1 rc1.

Please verify the packages and files according to
https://wiki.isc.org/bin/view/QA/KeaReleaseProcess, "4. Sanity Checks" chapter
and your imagination.
Before starting any checks. please, state in Sanity Checks issue in GitLab
what check you are doing in a thread/discussion (not as comment).
When you finish given check state in the same thread/discussion what is the result.
This way we know what is covered upfront and we can avoid repeating ourselves.

Release content is located on:
1) [tarballs] repo.isc.org in the following folders:
   /data/shared/sweng/kea/releases/1.8.1-rc1
   /data/shared/sweng/kea/releases/premium-1.8.1-rc1
   /data/shared/sweng/kea/releases/subscription-1.8.1-rc1

SHA256 (kea-1.8.1.tar.gz) = 52020cb16889484b661746d7fc4c7cd88974b1af5b7fc436eb6e69c62eb83734
SHA256 (kea-subscription-1.8.1.tar.gz) = 4bc6e61cf4a4b00ca5dc51b24086ed76703daad4f7ad97c1c5ffaeca3e8c7002
SHA256 (kea-premium-1.8.1.tar.gz) = a95de737c0bf29bbc8b8d351420cd05322003a69e04a79d866cde8512f167f1f

2) [rpm/deb packages] on packages.isc.org, exact packages versions are stored here:
    https://jenkins.isc.org/job/kea-1.8/job/pkg/13/
    Release version is 1.8.1-isc0000920201106154401 (please verify if it is this version while installing).
    Install instruction is here: https://wiki.isc.org/bin/view/QA/KeaReleaseProcess, chapter 4. Sanity Checks, point 9.