feat: add template for typescript

[codebytere]

Adds a custom templater for TypeScript:

npx create-electron-app my-new-app --template=typescript.

• I have read the contribution documentation for this project.
• I agree to follow the code of conduct that this project follows, as appropriate.
• The changes are appropriately documented (if applicable).
• The changes have sufficient test coverage (if applicable).
• The testsuite passes successfully on my local machine (if applicable).

[malept]

I'm very happy to see another built-in template!

[codecov]

Codecov Report

Merging #1319 into master will increase coverage by 24.84%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           master    #1319       +/-   ##
===========================================
+ Coverage   41.53%   66.37%   +24.84%     
===========================================
  Files           4       70       +66     
  Lines         183     2040     +1857     
  Branches       37      383      +346     
===========================================
+ Hits           76     1354     +1278     
- Misses         95      535      +440     
- Partials       12      151      +139

Impacted Files	Coverage Δ
...ages/template/typescript/src/TypeScriptTemplate.ts	100% <100%> (ø)
packages/maker/snap/src/MakerSnap.ts	100% <0%> (ø)
...es/api/core/src/api/init-scripts/init-directory.ts	93.75% <0%> (ø)
packages/api/core/src/util/index.ts	100% <0%> (ø)
packages/api/core/src/util/publish-state.ts	85.36% <0%> (ø)
packages/utils/async-ora/src/index.ts	100% <0%> (ø)
packages/maker/wix/src/util/author-name.ts	80% <0%> (ø)
packages/plugin/webpack/src/WebpackPlugin.ts	30.41% <0%> (ø)
packages/maker/rpm/src/MakerRpm.ts	94.73% <0%> (ø)
packages/installer/base/src/Installer.ts	75% <0%> (ø)
... and 58 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d337355...09c2858. Read the comment docs.

[malept]

LGTM!

[malept]

We'll need to add a page to the electronforge.io docs before we make a new beta release.