Adds the gitlens icon to settings editor and welcome page

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

Updates dependencies

Replaces git content provider with git fs provider
Adds Buffer output support to git calls

Adds new ${changes} and ${changesShort} template tokens
Adds support for prefixes and suffixes around tokens
Fixes missing/mismatched token option issues

Renanes "Compare x with" commands

Removes Uri monkey patch as it no longer will work
See 03432806c8
Stops encoding uris in .toString calls

Removes gitlens.advanced.git setting

Changes from out to dist
Adds size-plugin (commented out for now)
Adds image cache to improve bundle performance

Adds new webpack tree shaking plugin

Uses webpack for all of it

Changes rebase & reset terminal commands to apply to all commit nodes

Consolidates ui dependencies & build into main

Preserves spaces in format strings