Format sqlproj file XML on serialization

[Benjin]

Fixes #10772

[udeeshagautam]

if you already have great, if not, can you please check with @yualan / @dzsquared that there is nothing additional required in updating third part notice?

[Benjin]

Chatted with CELA per their recommendation, and we're all clear.

[udeeshagautam]

Build fails with this - looks you need to cpoy d.ts of xml formatter in extension

extensions/sql-database-projects/src/models/project.ts(10,28): Could not find a declaration file for module 'xml-formatter'. 'D:/a/1/s/extensions/sql-database-projects/node_modules/xml-formatter/index.js' implicitly has an 'any' type.
Try npm install @types/xml-formatter if it exists or add a new declaration (.d.ts) file containing declare module 'xml-formatter';

[Benjin]

@udeeshagautam That last commit was the result of running npm install @types/xml-formatter, so I must still be missing something. Everything's building locally, so I must have some state that's cached that agents don't yet. I'll try a few things to get that .d.ts file.

[coveralls]

Coverage increased (+0.2%) to 34.419% when pulling 05ab8b4 on benjin/xmlPrettify into c8a3fbc on master.