baldur: should verify the namespace syntax when reading baldur.properties

[jburke-cadc]

In baldur.properties, the namespace is the second value in the org.opencadc.baldur.entry property. baldur checks that each namespace is a valid regex expression. But baldur does not check the syntax of the namespace.

An example namespace in the regular expression ^cadc:BLAST/.*: where ^ is the start of the regex, cadc:BLAST/ is the namespace, and .* matches any characters after the namespace.

Look at what raven is doing to verify the namespace.