Tasks workflow forms

[igorline]

Proper workflow to work with staked tasks:

1. Manager creates and assign task for the user with specified address Screen to add new staked task #72
   We batch 4 wallet operations here:

• create task (T),
• move funds to respecting task within colony (T),
• set payouts for the task (T),
• sign user assignment operation on the manager side (S)

2. User should accept task

We batch 3 wallet operations here:

• sign user assignment on assignee side (S),
• send transaction to accept assignment (T),
• submit deliverable and rating for manager (T)

3. Manager should set rating for assignee task accomplishment
   
   We batch 2 wallet operations here:

• submit task work rating for assignee (T),
• reveal user rating (T)

4. User should claim payout to receive tokens
   
   We batch 3 wallet operations here:

• reveal manager rating (T),
• finalize task (T),
• claim payout (T)

(T) and (S) are operations requiring sending of transaction and signing of the operation respectively

Related UI task for batching transactions: #278

[igorline]

@romochka, keep in mind, that every transaction can fail, be rejected by user, tab can be closed, etc...
So user should be able be continue the process from any point.