perf: Lazy load React Ace

[kgabryje]

SUMMARY

ace-builds was 1 of the largest libraries in our bundle. It was always fetched when opening a dashboard even though it's only used in dashboard's edit mode (if there are markdown components), SQL lab, and SQL Editor popover in Explore.
This PR implements lazy loading that library.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Notice that we no longer fetch a 1.3MB chunk when opening a dashboard

Before:

After:

TESTING INSTRUCTIONS

1. Open a dashboard
2. Verify that the chunk containing ace-builds is not fetched initially
3. Open edit mode and try to edit a markdown component - verify that it works fine
4. Open SQL Lab - verify that SQL editor works fine
5. Open a chart and metrics edit popover - verify that SQL editor works fine

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[mistercrunch]

Oh nice! Looks like this will positively impact the Explore page loading times positively too

[mistercrunch]

LGTM