Property validation for owned project-system property pages

[adamint]

Summary

With the pending completion of client-side validation for property values, it would be a good idea to go through our owned property pages and, where applicable, add property validation.

[drewnoakes]

Some ideas:

• Root namespace is limited in what characters are allowed
• File paths cannot contain certain characters
• Package ID cannot contain spaces or characters that are invalid in URLs
• Assembly versions must be something like 0.0.0 or 0.0.0.0 (don't quote me on this!)
• Package versions must be something like 0.0, 0.0.0, 0.0-foo, 0.0.0-bar, etc (again, find a proper source to verify)
• Project URL and Repository URL must be a valid URL (we should not use RegEx for this though)