HPCC-9137 Add note re:Fedora repository

Fix HPCC-9137 Add note re:Fedora repository
Update to Installation doc.

Signed-off-by: g-pan <greg.panagiotatos@lexisnexis.com>
Merge pull request #4234 from g-pan/H9137-InstNote

HPCC-9137 Add note re:Fedora repository

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>