Don't install docs on travis-ci

MSP-9337

Disable RI and RDoc when installing gems on travis-ci.

(cherry picked from commit 4ba9aaed)
Tag UI related specs with :ui

MSP-9337

Allows ui specs to run separately.  Part of effort to break up travis-ci
builds to prevent Killed processes due to memory exhaustion.

Conflicts:
	spec/app/models/metasploit/framework/command/base_spec.rb
	spec/app/models/metasploit/framework/command/check/help_spec.rb
	spec/app/models/metasploit/framework/command/check/simple_spec.rb
	spec/app/models/metasploit/framework/command/check_spec.rb
	spec/app/models/metasploit/framework/command/search/argument/column_spec.rb
	spec/app/models/metasploit/framework/command/search/help_spec.rb
	spec/app/models/metasploit/framework/command/search/table_spec.rb
	spec/app/models/metasploit/framework/command/search_spec.rb
	spec/app/models/metasploit/framework/command/use/help_spec.rb
	spec/app/models/metasploit/framework/command/use/set_metasploit_instance_spec.rb
	spec/app/models/metasploit/framework/command/use_spec.rb
	spec/app/models/metasploit/framework/ui/command_line_interface/command/base_spec.rb
	spec/app/models/metasploit/framework/ui/command_line_interface/command/command_line_interface/help_spec.rb
	spec/app/models/metasploit/framework/ui/command_line_interface/command/command_line_interface_spec.rb
	spec/app/models/metasploit/framework/ui/console/command/base_spec.rb
	spec/app/models/metasploit/framework/ui/console/command/exploit/help_spec.rb
	spec/app/models/metasploit/framework/ui/console/command/exploit/simple_spec.rb
	spec/app/models/metasploit/framework/ui/console/command/exploit_spec.rb
	spec/lib/metasploit/framework/ui/meterpreter/console/command_dispatcher/core_spec.rb
	spec/lib/msf/ui/command_dispatcher/core_spec.rb
	spec/msfvenom_spec.rb

(cherry picked from commit f6587c3)
Split ui and non-ui specs on travis-ci

MSP-9228
(cherry picked from commit d605a590ff96b116baf74e6e7734eb4bec3160de)

Conflicts:
	.travis.yml
Separate cache and content specs with tags

MSP-9337

The content specs are long running since they load all the modules files
while the non-content, cache specs just can be logically grouped
together.
(cherry picked from commit 99220721bb387376355eebe76d51f66580dec83f)

Conflicts:
	.travis.yml