Fix module manifest

There were actually several problems with the released version on the PowerShell Gallery, but the main problem was that there was no link to a GitHub project where people could tell me about their problems.

The module manifest was also out of date in several ways, having been automatically generated -- this is fixed.

There was no way to update passwords without two actions delete/create. I've added a -Force parameter to force (re)prompting so you can change passwords using -Force -Store together.

To install, use PowerShellGet or the OneGet PackageManagement module.

Install-Module BetterCredentials