change the candidate assessment page to dialog
add roles list context menu
candidates frontend & backend new functionalities

  [PT 46356045] filter candidate list
  [PT 50160713] candidate blacklist support
refine the candiadtes view filter implementation
[50238471] disable 'schedule new' button when appicable

When candidate isn't in an interview status, such as marked-as-fail ready, the 'schedule
new' button should be invisible.

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge branch 'master' of https://github.com/vmw-tmpst/heroapp-LetsHire
[49574871] basic function to support assign multiple candidates

main function ready
To-do-list
1 error handling
2 ajax refresh after assign operation completes.

Signed-off-by: Henry Chen <hchen@vmware.com>
fix a syntax error
Signed-off-by: Henry Chen <hchen@vmware.com>
rollback an unintended change

Signed-off-by: Henry Chen <hchen@vmware.com>
fix a regression

Signed-off-by: Henry Chen <hchen@vmware.com>
Merge pull request #176 from Henry-CF/assign_candidates

[49574871] basic function to support assign multiple candidates