Chisel v5.0.0-M1

API Modification

• [chisel5] git subtree add FIRRTL (by @seldridge in #2982)
• [chisel5] Build FIRRTL in-tree, not published dependency (by @seldridge in #2983)
• [chisel5] Remove SFC Compiler from FIRRTL Subtree (by @seldridge in #2984)

Build and Internal Changes

• Chisel5 publishing (by @jackkoenig in #3044)
  Change published artifact from edu.berkeley.cs::chisel3 to org.chipsalliance::chisel. Set up automated publishing for 5.0-SNAPSHOT (to s01.oss.sonatype.org because Chips Alliance is a relatively new Sonatype organization). Merge old firrtl, chisel3-macros, chisel3-core, and chisel3 artifacts into a single artifact: chisel.
• Update Mergify config and add generation script to this repository (by @jackkoenig in #3059)
• [CI] Add integrationTests for execution-driven tests (by @jackkoenig in #3061)

Full Changelog: a005498...v5.0.0-M1