Set PRERELEASE for branch

MSP-9650
Merge branch 'staging/metasploit-concern' into feature/extraction

MSP-9652
Extract Metasploit::Pro::Loading and initializer to Metasploit::Concern::Loader

MSP-9652

Metasploit::Concern::Loader is more generic as it will scan for concerns
under any root pathname and not just for mdm concerns.
Concern loading initializer

MSP-9652

Add config/initializer/load_concerns.rb, which will scan the
application and all engines for app/concerns and load those concerns
with Metasploit::Concern::Loader.
Ignore built gems

MSP-9652
Bump version

MSP-9652
Add usage docs

MSP-9652
Ignore .ruby-* files

MSP-9652
Work-around bug in shoulda-matchers 2.6.0

MSP-9652
Land #1

Merge branch 'feature/extraction' into staging/metasploit-concern
post merge step. updating prerelease
Updating the LICENSE information.
Fill in gemspec description and summary

MSP-9795
Move documentation gems out of gemspec

MSP-9795

The documentation gems: yard, kramdown, and redcarpet, do not need to be
gemspec development dependencies because gems that depend on
metasploit-concern are not required to use its yard.rake.
Add semantic version pinning for activesupport

MSP-9795

`gem build` now warning if a gem isn't pinned using `~>` under the
assumption that most gems have adopted semantic versioning, so add it
for activesupport.
Disable PRERELEASE example on pull requests

MSP-9795

When travis-ci builds a pull request, it attempts the build on both the
source and target branch, but PRERELEASE is only set for the source
branch, so if TRAVIS_PULL_REQUEST is set and not 'false', then don't
check the value of PRERELEASE as it will be still set to the source
branch relative name instead of that target branch relative name.
Merge branch 'staging/metasploit-concern'

MSP-9795
Remove PRERELEASE from master

MSP-9795