Update Octicons to v10 (#12240)

* Update Octicons to v10

Besides a few renames, these icons are no longer present in v10 that we've
used, so had to change:

file-symlink-directory -> file-submodule
internal-repo -> repo
repo-force-push -> repo-push
repo-template-private -> repo-template

Fixes: https://github.com/go-gitea/gitea/issues/11889
Ref: https://github.com/primer/octicons/releases/tag/v10.0.0

* add custom sliders svg for removed octicon-settings

* apply suggestion

* fix triangles and use play on admin dashboard

* add custom mirror svg

* add missing build files

* unify custom svgs

* move to octicon-repo-clone to gitea-mirror

* use octicon-x on conflicts

* tweak timeline icons

* tweak comment buttons

* update settings icon to octicons v1

* switch to octicon-mirror and octicon-tools

* replace two wiki buttons with octicons

* remove whitespace in svg sources

* Fix filepath basename on Windows for SVG bindata (#12241)

* move octicons to devDependencies

* move back to dependencies

* move svgo to devDependencies again

Co-authored-by: Cirno the Strongest <1447794+CirnoT@users.noreply.github.com>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

public/img/svg/octicon-mail.svg

@@ -1 +1 @@
-<svg viewBox="0 0 14 16" class="svg octicon-mail" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M0 4v8c0 .55.45 1 1 1h12c.55 0 1-.45 1-1V4c0-.55-.45-1-1-1H1c-.55 0-1 .45-1 1zm13 0L7 9 1 4h12zM1 5.5l4 3-4 3v-6zM2 12l3.5-3L7 10.5 8.5 9l3.5 3H2zm11-.5l-4-3 4-3v6z"/></svg>
+<svg viewBox="0 0 16 16" class="svg octicon-mail" width="16" height="16" aria-hidden="true"><path fill-rule="evenodd" d="M1.75 2A1.75 1.75 0 000 3.75v.736a.75.75 0 000 .027v7.737C0 13.216.784 14 1.75 14h12.5A1.75 1.75 0 0016 12.25v-8.5A1.75 1.75 0 0014.25 2H1.75zM14.5 4.07v-.32a.25.25 0 00-.25-.25H1.75a.25.25 0 00-.25.25v.32L8 7.88l6.5-3.81zm-13 1.74v6.441c0 .138.112.25.25.25h12.5a.25.25 0 00.25-.25V5.809L8.38 9.397a.75.75 0 01-.76 0L1.5 5.809z"/></svg>