Replaced gogits go-gogs-client with go-sdk

Replace GOGS with GITEA in variable names

Follows GNU Coding Standards, see
https://www.gnu.org/prep/standards/html_node/Standard-Targets.html#Standard-Targets

Closes #102

Still use GOGS_WORK_DIR and GOGS_CUSTOM env variables
as a fallback if the equivalent GITEA_* are not set,
warning user about the need for change.

Does not change "gogs" to "gitea" in webhook type name
Because "gogs" hook type is part of the API (routes) and used
in templates...

Closes #87

CSS: Stronger colors for diffs

to reduce code-duplicity

Disable HTTP cloning

Use the rev-parsed sha1 commit id in urls to repo files,
instead of the abbreviated version.

Fix rendering of non-markdown readme files

* Replace gogits/git-module dependency with go-gitea/git

Fixes #92

* Remove git alias for git module import (not needed)

Review issue and pull templates, drop unused contributing file

The CONTRIBUTING.md from root dir will be used by github

Use a list for owners (nitpick response)

Fix imports found by goimports.

Refactor editorconfig middleware

😊

Fix 500 when repo has invalid .editorconfig

Creating a notice instead

Use tabs in Makefiles

Refactoring of the makefile