✨Flags for PROS 4 Beta Templates

[omegaStag]

Summary:

Adds a beta depot to the remote depots (currently only contains a 3.7.3 kernel template labeled as 4.0.0), adds --pros-4 flags for conductor commands to use the beta depot

Motivation:

For PROS 4 beta testing

References (optional):

Contains changes made in PR #253 and PR #251 and closes their respective issues, #243, #241

Test Plan:

• Making project with --pros-4 should use beta depot
• Upgrading with pros c upgrade --pros-4 on a PROS 3 project should have a warning
• Downgrading with pros c apply-template kernel@3.x.x on a PROS 4 project should have a warning
• pros c q --pros-4 should list beta templates too

[ayushuk]

Will be revisited when the pros 4 is up on the depot. Was tested with dummy pros 3 template with adjusted metadata.

[WillXuCodes]

Overall functionality is good, just needs one minor naming change.

[kunwarsahni01]

Discard Changes

[kunwarsahni01]

FIWB