Git: Make repository picker available to other extensions

[joaomoreno]

No description provided.

[joaomoreno]

The command is git.api.getRemoteSources and it has a bag of options:

export interface PickRemoteSourceOptions {
	readonly providerLabel?: (provider: RemoteSourceProvider) => string;
	readonly urlLabel?: string;
}

Usage:

await commands.executeCommand('git.api.getRemoteSources', {
	providerLabel: (provider: RemoteSourceProvider) => `Test this for ${provider.name}`,
	urlLabel: `Test this for URL`
});

cc @egamma