Ability to add an activity in between existing tiles

[apandura-tibco]

There should be a provision to add an activity in between tile.

Flows:

• [x] Show add activity in between tile
• [x] Restrict users from adding tile when the row already has 10 tiles
• [x] Restrict users from adding tile when the longest path from position is already 10 tiles
• [x] Filter return activity from the list of installed contributions in add activity overlay window

Streams:

• [x] Show add activity in between tile
• [x] Restrict users from adding tile when the row already has 10 tiles