Ticket 49990 - Increase the default FD limits
Description: As discussed in the ticket, this fix sets the maxdescriptors
to the maximum allowed by the OS/systemd. If this limit can
not be obtained then we fall back to 8192 as the limit
https://pagure.io/389-ds-base/issue/49990
Reviewed by: tbordaz & firstyear(Thanks!!)
(cherry picked from commit 8ca142034a051122b78bdaa3a948d3c50d4cca7e)
(cherry picked from commit 2c583a97cffa54a7da9922215ae37156174a37c5)