Multiple GitGraph improvements: Exclude PR heads, Add branch/PR links, Show only certain branches, (#12766)

* Multiple GitGraph improvements.

Add backend support for excluding PRs, selecting branches and files.

Fix #10327

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

* as per @silverwind

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

* as per @silverwind

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

* Only show refs in dropdown we display on the graph

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

* as per @silverwind

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

* use flexbox for ui header

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

* Move Hide Pull Request button to the dropdown

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

* Add SHA and user pictures

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

* fix test

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

* fix test 2

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

* fixes

* async

* more tweaks

* use tabs in tmpl

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

* remove commented thing

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

* fix linting

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

* Update web_src/js/features/gitgraph.js

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

* graph tweaks

* more tweaks

* add title

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

* fix loading indicator z-index and position

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

options/locale/locale_en-US.ini

@@ -822,6 +822,8 @@ audio_not_supported_in_browser = Your browser does not support the HTML5 'audio'
 stored_lfs = Stored with Git LFS
 symbolic_link = Symbolic link
 commit_graph = Commit Graph
+commit_graph.select = Select branches
+commit_graph.hide_pr_refs = Hide Pull Requests
 commit_graph.monochrome = Mono
 commit_graph.color = Color
 blame = Blame