[#1819] Upgrade Requests to 2.3.x

Only a minor change in the resource proxy extension (look like the
content-length header is no longer added by default).
Role translations.
(cherry picked from commit c5302ef)
We have translated.
(cherry picked from commit 6dc25db)
Translated lines 4801-5600
(cherry picked from commit ae7825b)
We have translated.
(cherry picked from commit 1b3f739)
We have translated.
(cherry picked from commit 1cb6a12)
We have translated.
(cherry picked from commit 50897e5)
Add translation of lines from 4400 to 4800
(cherry picked from commit fe0acaa)
Preklad riadkov 600-800
(cherry picked from commit 136ed95)
preklad riadkov 0 - 600
(cherry picked from commit 337135d)
Fix translation
(cherry picked from commit 9535930)
Fix some translation
(cherry picked from commit 31920fe)
translated lines 801-1600
(cherry picked from commit 575e2ea)
Translation for rows 4002-4401
(cherry picked from commit 77e19bd)
We have translated.
(cherry picked from commit 852cae0)
Dočasná verzia
(cherry picked from commit f845155)
Doplnený preklad od 2801-3200
(cherry picked from commit bca6733)
Final Version 5600-6400
(cherry picked from commit 46f6bcf)
Slovak translation lines 4000-4400 and 1 correction in Czech translation
(cherry picked from commit afe14d6)
Slovak translation fixed typo
(cherry picked from commit 3911cc9)