Get pg as a dependency of metasploit_data_models

[#38274165]

metasploit_data_models already declares pg as a runtime dependency in
its gemspec, so there is no need to add pg as a direct dependency of
metasploit-framework, since metasploit-framework only needs pg for
metasploit_data_models.
Remove cred_files migration

[#41837027]

Mdm::CredFile is only used in Pro, so for metasploit_data_models 0.4.0,
Mdm::CredFiles has been moved to Pro, so the migration has been moved to
Pro too.
Made changes as described in Redmine issue 7605
Updates normalize_uri()

This function should not remove the trailing slash, because you may
end up getting a different HTTP response.  The new function also
allows multiple URIs as argument, and will just merge & normalize
them together. [SeeRM #7733]
Correct rspect to the correct behavior
Correctly use normalize_uri()

normalize_uri() should be used when you're joining URIs.  Because if
you're merging URIs after it's normalized, you could get double
slashes again.
This is a string, not a variable
Fix check
added module for cve-2013-1412
uri normalization in the old way
I wanna know where it's stored
Fix errant use of .to_s instead of .path
Fix scrutinizer checks
Oh don't be so sensitive about it.

Fixnum vs String
Use normalize_uri for URI