Update bootstrap.sh

[ldrrp]

Automatically grab latest mariadb available

Issue #, if available:

This relates to all the below issues:
#425 #406 #344 #409 #425

Description of changes:

Automatically detect latest minor versions for pinned versions of mariadb. I used rackspace mirror because the original mirror does not allow folder scanning. Left it in a variable for others to update as needed for their countries.

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[ldrrp]

This was only tested and working for 2.10.3 branch. May vary for older versions but altering the variables might get you the desired behavior for the other branches

YUM_VERSION_PREFIX="11.8" 
MARIADB_VERSION_PREFIX="11.5"
FEDORAVERSION="38"