[Feature Request]: Multiple instances (allow fallback to a second custom invidious server)

Guidelines

[X] I have searched the issue tracker for open and closed issues that are similar to the feature request I want to file, without success.
[X] I have searched the documentation for information that matches the description of the feature request I want to file, without success.
[X] This issue contains only one feature request.

Problem Description

I have an issue where my primary Invidious instance fails, but then FreeTube ("FT") will fall back to one of the hard-coded instances.

I would like to put in a second instance instead of using a random public instance

Proposed Solution

Allow multiple instances - maybe using a multiline textbox

I would prefer it if I could put a list of instances, in order of priority, into a text box so that I can have it fall back to my other private instance instead of a public instance. You could also list a public instance at the end, as a last resort, if the other instances in the list did not work.

Alternatives Considered

There are no alternatives other than forking FT project and adding code in yourself

Issue Labels

improvement to existing feature, new feature, new optional setting

Additional Information

An example of this list could be:

http://192.168.1.100:3000
http://192.168.1.101:3000
https://invidious.privacyredirect.com:443

The above list is in order of priority.

FreeTubeApp / FreeTube