move build time and notifications

[kspeer825]

Description of change

https://jira.talendforge.org/browse/TDL-16944 Move build time to avoid conflicts with contractors and internal teams. 6:00am UTC -> 1:00 UTC (8:00pm EST, 6:30am IST)

Move slack notifications to new channel.

QA steps

• [ ] automated tests passing
• [ ] manual qa steps passing (list below)

Risks

Rollback steps

• revert this branch