Enforce tab indentation in templates (#15289)

* Enforce tab indendation in templates

This adds editorconfig-checker [1] to lint the template files so they
conform the editorconfig files. I fixed all current identation issues
using the fix mode of eclint [2] and some manual corrections.

We can extend this linting to other files later, for now I'd like this
PR to focus on HTML template files only.

[1] https://github.com/editorconfig-checker/editorconfig-checker
[2] https://github.com/jedmao/eclint

* fix indendation

Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

templates/repo/migrate/github.tmpl

@@ -6,7 +6,7 @@
 				{{.CsrfTokenHtml}}
 				<h3 class="ui top attached header">
 					{{.i18n.Tr "repo.migrate.migrate" .service.Title}}
-                    <input id="service_type" type="hidden" name="service" value="{{.service}}">
+					<input id="service_type" type="hidden" name="service" value="{{.service}}">
 				</h3>
 				<div class="ui attached segment">
 					{{template "base/alert" .}}

templates/repo/migrate/gitlab.tmpl

@@ -6,7 +6,7 @@
 				{{.CsrfTokenHtml}}
 				<h3 class="ui top attached header">
 					{{.i18n.Tr "repo.migrate.migrate" .service.Title}}
-                    <input id="service_type" type="hidden" name="service" value="{{.service}}">
+					<input id="service_type" type="hidden" name="service" value="{{.service}}">
 				</h3>
 				<div class="ui attached segment">
 					{{template "base/alert" .}}

templates/repo/migrate/gogs.tmpl

@@ -62,7 +62,7 @@
 								<label>{{.i18n.Tr "repo.migrate_items_releases" | Safe}}</label>
 							</div>
 						</div>
-					  -->
+						-->
 					</div>
 
 					<div class="ui divider"></div>