Remove GoGet option from repository and handle it with ?go-get=1 instead

The normal go get protocol is to show the go-import meta tag when ?go-get=1 is appended to the url. This commit implements that behaviour and cleans the go-get option from the repository settings page.

conf/locale/locale_en-US.ini

@@ -281,8 +281,6 @@ init_readme = Initialize this repository with a README.md
 create_repo = Create Repository
 default_branch = Default Branch
 mirror_interval = Mirror Interval (hour)
-goget_meta = Go-Get Meta
-goget_meta_helper = This repository will be <span class="label label-blue label-radius">Go-Getable</span>
 
 need_auth = Need Authorization
 migrate_type = Migration Type