Add Support for FileInstallationStore

[stevengill]

Description

In addition to the default MemoryInstallationStore, BoltJS should offer the option of a FileInstallationStore. Developers can import this new store and use it instead of the default for a more persistent storage experience.

What type of issue is this? (place an x in one of the [ ])

• enhancement (feature request)

Requirements (place an x in each of the [ ])

• I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue.

[seratch]

This is related to slackapi/node-slack-sdk#1278
@misscoded Do we have things to do on the bolt-js side?

[seratch]

Once the @slack/oauth package switches the default to the file installation store, we can close this issue.

[misscoded]

@seratch

Do we have things to do on the bolt-js side?

Apologies, I missed this -- I believe the only thing to be done on the Bolt side is to ensure that it's imported/exported from the @slack/oauth side of things. And any associated documentation, if applicable.

I almost think it worth narrowing/editing this issue to just be FileInstallationStore to accurately reflect the work that's been done. Thoughts?

[seratch]

@misscoded

I almost think it worth narrowing/editing this issue to just be FileInstallationStore to accurately reflect the work that's been done. Thoughts?

I totally agree on this 👍