Changes working tree/branch comparision selection to be per-comparison

Replaces "recent incoming changes" node

Adds a Show All command to the Show More nodes
Improves experience after starting a new search or compare
Fixes issues with maxCount == 0

Renames existing stash save command
Adds new stash save command (per file)

Updates GitLens logo
Adds CodeStream sponsor

Renames showCommitInResults to showCommitInView
Renames showFileHistoryInResults to showFileHistoryInView

Updates stash icons

Adds stash changes to stashes toolbar
Adds apply changes to stashes menu
Fixes stash/apply changes to honor repository context

Changes changelog image links to permalinks
Moves all images for docs into a docs folder
Removes unused images

Closes #470 - Adds fetch command to Repository explorer

Closes #354 - Adds line history explorer (wip)
Closes #456 - Adds repository status to the repository nodes

Renanes "Compare x with" commands

Closes #419 - Make blame heatmap color configurable

Also adds icons for prev/next and places them into the editor toolbar