tweak: add cancel button to deploy dev center

[ivanma9]

Created a cancel button. Made it cancel deployments. Issue #1135

[CLAassistant]

All committers have signed the CLA.

[KernelDeimos]

Hello again, please correct me if I'm wrong but - upon manual and further review - cancelling doesn't really do anything, does it? It seems to me it just gives the user the illusion that something is being cancelled but deployment continues as normal. This could still be helpful since it allows the user to start another deployment again quickly if they made a mistake, but that might actually cause issues if there's already a concurrent deployment happening that they don't know about.

[KernelDeimos]

Closing due to no-response, and PR doesn't perform the function that's claimed