Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

 templates/oscar#	gelöscht:       searx/static/themes/oscar/fonts/glyphicons-halflings-regular.ttf

* oscar theme: code from searx/plugins/infinite_scroll.py
* simple theme: new implementation

Co-authored-by: Markus Heiser <markus.heiser@darmarIT.de>

https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes#attr-lang
https://www.w3.org/TR/REC-xml/#sec-lang-tag

This commit remove the need to update the brand for GIT_URL and GIT_BRANCH:
there are read from the git repository.

It is possible to call python -m searx.version freeze to freeze the current version.
Useful when the code is installed outside git (distro package, docker, etc...)

In the templates and the /config (JSON) the usage of the 'brand.*' name
space is replaced by 'searx.get_setting' function.

- new_issue_url          --> get_setting('brand.new_issue_url')
- brand.GIT_URL          --> get_setting('brand.git_url')
- brand.PUBLIC_INSTANCES --> get_setting('brand.public_instances')
- brand.DOCS_URL         --> get_setting('brand.docs_url')
- brand.ISSUE_URL        --> get_setting('brand.issue_url')
- brand.CONTACT_URL      --> get_setting('general.contact_url', '')

The macro 'new_issue' from searx/templates/*/messages/no_results.html
is now imported with context::

    {% from '__common__/new_issue.html' import new_issue with context %}

To get *public instances URL* from context's 'get_setting()' function::

    get_setting('brand.public_instances','')

Macro's prototype does no longer need the 'new_issue_url' argument and has been
changed to::

    macro new_issue(engine_name, engine_reliability)

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

Adjust thumbnail sizes to fill the container width

In webapp.py, there is a new function "get_translations" lists available translations

Close #2064