A number of fixes to the admin guide.

First, add missing reqDN indexing.
Second, convert most references to bdb/hdb to mdb, unless the section was specific to bdb/hdb.
Third, use "dc=example,dc=com" consistently throughout the example set

Howard Chu authored Jun 03, 2011 and Quanah Gibson-Mount committed Jun 08, 2011

slapcat will always be self-consistent since the contextCSN is
snapshotted at the beginning of the dump.

n-way-multimaster png and svg files.
First attempt to visualise refreshOnly and refreshAndPersist modes of LDAP Sync Protocol.

work in progress. Expand introduction, move slurpd-replacement lower.