Core & SystemUI: RU translation

PS1: Rephrased "lockscreen_discharging" and moved it to cm_strings.
     Brought back "lockscreen_plugged_in" from AOSP, to prevent merge conflicts.

PS2: Updated translation for Pie controls and Quick Settings.

PS3: Moved "lockscreen_discharging" back to strings.xml, like in original translation.
     Fixed a typo in "lockscreen_plugged_in", now it's identical to AOSP.

PS4: Updated and rephrased Permlabs. AOSP russian translation starts them with capital
     letter and uses nouns instead of verbs.

PS5: Added translation for Mock SMS permissions and "progress_nomediapresent" message.

PS6: Updated plurals to fix AOSP bug, where "1 item" was also displayed for 21, 31, ...
     Will be also proposed to AOSP Code Review.
     Original discussion here (translators only): http://goo.gl/tD5cBg

PS7: Rephrased "navbar_menu_" strings, more precise description now.

PS8: Made changes suggested by Marco: removed msgid in "lockscreen_plugged_in" and an
     unneeded comment for "progress_nomediapresent".

PS9: Reverted plurals' fix. Will create an AOSP bugtracker entry for this.

Change-Id: Ied3d421ba3f84eca3248b6afab4721aa623d528e