Cloned from https://bugzilla.redhat.com/show_bug.cgi?id=1798668

Description of problem:
Configure default MongoDB cache to be 20% of RAM in the Satellite server. See KCS [1] for more info.

Version-Release number of selected component (if applicable):
Satellite 6.6

How reproducible:
N/A

Steps to Reproduce:
1. Mongod process with the WiredTiger engine consumes up to 50% of RAM on Satellite. See https://docs.mongodb.com/manual/core/wiredtiger/#memory-use On larger Satellite installations, MongoDB ends up consuming a large amount of memory affecting other Satellite tasks.
2. With internal testing from the Performance Engineering team, it has been found that using 20% of RAM is ideal for MongoDB WiredTiger cache.

Actual results:
There is no tuning for WiredTiger cache size so it goes on to consume up to 50% of RAM in Satellite.

Expected results:
Configure default MongoDB WiredTiger cache size to be 20% of RAM in the Satellite server.

Additional info:
[1] https://access.redhat.com/solutions/4505561