Display provider aliases in provider panel

[dbanck]

Background

In #701, we introduced a provider panel with a list of providers for a module.

Problem Statement

The current implementation displays the type, namespace, version constraints and installed version of each provider. Users can only know what aliases are providers available under by finding and reading the relevant parts of the configuration.

Expected User Experience

Users can see aliases in the same pane alongside provider requirements.

Proposal

• Update the LS workspace command terraform-ls.module.providers (introduced in https://github.com/hashicorp/terraform-ls/pull/712) to include a list of aliases
• Update the client-side panel to include those aliases

Notes

• When deciding on the UI details, keep in mind that we also want to display alternative provider names (#855).