Support new schema endpoint and metadata operations

[dvdsgl]

• Adds glide.getApps() and glide.getAppNamed(...).
• Adds app.getTables() and app.getTableNamed(...).
• Adds table.getSchema().

They allow more flexible handling of apps and tables–for example:

// Get all users of all apps on team:
const allUsers = [];
const apps = (await glide.getApps()) ?? [];
for (const app of apps) {
      const usersTable = await app.getTableNamed("Users");
      const users = await usersTable!.getRows();
      allUsers.push(...users);
}

An Enterprise customer asked for these.

[chkn]

Lovely improvements 🧑‍🍳

Just left a couple minor thoughts/suggestions, nothing blocking.

[chkn]

I feel like we're sort of committing to this endpoint, at least for some period of time, by shipping it here.. Just making sure we're cool with that /cc @timwellswa

[dvdsgl]

I am prepared to change it. We will need to coordinate when we do, yes.

[chkn]

This doesn't make it clear to me that it's actually fetching the schema from Glide. Earlier in this sample, inventory is created by specifying the columns and their types, so I'd assume this would just return that again:

  columns: {
    Item: "string",
    Description: "string",
    Price: "number",

    // Handle internal column names != display names
    Assignee: { type: "string", name: "7E42F8B3-9988-436E-84D2-5B3B0B22B21F" },
  },`

I'm assuming that is still needed to get strongly typed rows? Might be good just to clarify the relationship between these

[chkn]

Shouldn't this just be this.props.token now?

Suggested change

	token: process.env.GLIDE_TOKEN!,
	token: this.props.token!,

[chkn]

Same again?

Suggested change

	token: process.env.GLIDE_TOKEN!,
	token: this.props.token!,