Fix missing blank line to follow PythonStyleGuide in model.py.

Add links in sidebar for upcoming Sponsor views. Patch by: Pawel Solyga Review by: to-be-reviewed

Change key_name module usage to path_linkname module (fix to previous commit). Add comments about urls. Add Sponsor views urls for upcoming Sponsor views modules. Patch by: Pawel Solyga Review by: to-be-reviewed

Move path and link_name related functions and regex patterns to a new soc/logic/path_linkname.py module, and fix all dependencies. path/link_name functionality is becoming the generic way to identify entities in the Datastore in a URL-compatible way.

Make form field components use a smaller font, without shrinking the font of all text in the page body.

Replace common module with validate module. Move validation function from feed module to validate module and remove feed.py. Correct any usage of validation functions from common and feed modules into validate module. Patch by: Pawel Solyga Review by: to-be-reviewed

Add missing blank line to follow PythonStyleGuide in document.py

Fixed typo in DEF_CREATE_NEW_DOC_MSG.

Shrink the sidebar menu separately from the main body text.

Moved isLinkNameFormatValid function out of id_user module to new common module. This function is going to be used by other form validation functions that require to validate linkname (different kind of Groups, Programs etc). Patch by: Pawel Solyga Review by: to-be-reviewed