[wix-devs] Burn micro repo(s)

[Sean Hall]

I think these are the Burn related folders that we still need to move into
micro repos:

wix4/src/burn
wix4/src/ext/BalExtension
wix4/src/libs/balutil
wix4/src/libs/deputil

The easiest way would be to just throw them all into one repo. Otherwise,
we'll have to start looking at all the different parts. Here's what I think
are all the pieces:

wix4/src/burn
    burn engine (/engine - engine.lib plus headers)
    BA interface headers (/inc - BootstrapperEngine.h and
BootstrapperApplication.h)
    burn stub (/stub - burn.exe)
    samples (/samples)
wix4/src/ext/BalExtension
    actual extension (/wixext, /wixlib, /wixlib_arm)
    MBA host (/mba/host - mbahost.dll)
    MBA core (/mba/core - BootstrapperCore.dll)
    WixStandardBA (/wixstdba - wixstdba.dll)
    sample BA Functions (/samples)
wix4/src/libs/balutil
    base native BA, BA utility methods (balutil.lib)
    BA Functions interface header (/inc - BAFunctions.h)
wix4/src/libs/deputil
    deputil.lib

If we're going to split it up, I guess it would be one repo for the BA
interface headers, one repo for the Burn engine and stub and samples (and
deputil?), and one repo for the rest.