* Server-side syntax hilighting for all code

This PR does a few things:

* Remove all traces of highlight.js
* Use chroma library to provide fast syntax hilighting directly on the server
* Provide syntax hilighting for diffs
* Re-style both unified and split diffs views
* Add custom syntax hilighting styling for both regular and arc-green

Fixes #7729
Fixes #10157
Fixes #11825
Fixes #7728
Fixes #3872
Fixes #3682

And perhaps gets closer to #9553

* fix line marker

* fix repo search

* Fix single line select

* properly load settings

* npm uninstall highlight.js

* review suggestion

* code review

* forgot to call function

* fix test

* Apply suggestions from code review

suggestions from @silverwind thanks

Co-authored-by: silverwind <me@silverwind.io>

* code review

* copy/paste error

* Use const for highlight size limit

* Update web_src/less/_repository.less

Co-authored-by: Lauris BH <lauris@nix.lv>

* update size limit to 1MB and other styling tweaks

* fix highlighting for certain diff sections

* fix test

* add worker back as suggested

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

* upgrade to use testfixtures v3

* simplify logic

* make vendor

* update per @lunny

* Update templates/repo/empty.tmpl

* Update templates/repo/empty.tmpl

Co-authored-by: Lauris BH <lauris@nix.lv>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

Signed-off-by: Tamal Saha <tamal@appscode.com>

* Panic don't fatal on create new logger

Fixes #5854

Signed-off-by: Andrew Thornton <art27@cantab.net>

* partial broken

* Update the logging infrastrcture

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Reset the skip levels for Fatal and Error

Signed-off-by: Andrew Thornton <art27@cantab.net>

* broken ncsa

* More log.Error fixes

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove nal

* set log-levels to lowercase

* Make console_test test all levels

* switch to lowercased levels

* OK now working

* Fix vetting issues

* Fix lint

* Fix tests

* change default logging to match current gitea

* Improve log testing

Signed-off-by: Andrew Thornton <art27@cantab.net>

* reset error skip levels to 0

* Update documentation and access logger configuration

* Redirect the router log back to gitea if redirect macaron log but also allow setting the log level - i.e. TRACE

* Fix broken level caching

* Refactor the router log

* Add Router logger

* Add colorizing options

* Adjust router colors

* Only create logger if they will be used

* update app.ini.sample

* rename Attribute ColorAttribute

* Change from white to green for function

* Set fatal/error levels

* Restore initial trace logger

* Fix Trace arguments in modules/auth/auth.go

* Properly handle XORMLogger

* Improve admin/config page

* fix fmt

* Add auto-compression of old logs

* Update error log levels

* Remove the unnecessary skip argument from Error, Fatal and Critical

* Add stacktrace support

* Fix tests

* Remove x/sync from vendors?

* Add stderr option to console logger

* Use filepath.ToSlash to protect against Windows in tests

* Remove prefixed underscores from names in colors.go

* Remove not implemented database logger

This was removed from Gogs on 4 Mar 2016 but left in the configuration
since then.

* Ensure that log paths are relative to ROOT_PATH

* use path.Join

* rename jsonConfig to logConfig

* Rename "config" to "jsonConfig" to make it clearer

* Requested changes

* Requested changes: XormLogger

* Try to color the windows terminal

If successful default to colorizing the console logs

* fixup

* Colorize initially too

* update vendor

* Colorize logs on default and remove if this is not a colorizing logger

* Fix documentation

* fix test

* Use go-isatty to detect if on windows we are on msys or cygwin

* Fix spelling mistake

* Add missing vendors

* More changes

* Rationalise the ANSI writer protection

* Adjust colors on advice from @0x5c

* Make Flags a comma separated list

* Move to use the windows constant for ENABLE_VIRTUAL_TERMINAL_PROCESSING

* Ensure matching is done on the non-colored message - to simpify EXPRESSION

* Migrate to go modules

* make vendor

* Update mvdan.cc/xurls

* make vendor

* Update code.gitea.io/git

* make fmt-check

* Update github.com/go-sql-driver/mysql

* make vendor

To fix build failure on Windows/386

* Update makefile to use dep

* Migrate to dep

* Fix some deps

* Try to find a better version for golang.org/x/net

* Try to find a better version for golang.org/x/oauth2

closes #2040

upstream commit: acfa601240