Add --skipBuild flag

[osyrisrblx]

• and hoist --compilerVersion .check() to be near --compilerVersion .option()

Will be useful for roblox-ts compiler workflow which runs create-roblox-ts. It will:

1. Run with --skipBuild
2. Install local repo as roblox-ts dependency in template project
3. npm run build

[osyrisrblx]

Alternative idea: --localCompiler ./roblox-ts flag? This would do npm install ./roblox-ts and remove "roblox-ts" from the devDependencies list.

But maybe --skipBuild might have other use cases.