[Epic] TCM docs Q3

[p7nov]

Related dev. epic: https://github.com/tarantool/tarantool-cluster-manager/issues/819
PM ref.: https://www.notion.so/tarantool/TCM-973003d7aa254c7f802b2fae89f453e1?pvs=4
Product repo: https://github.com/tarantool/tarantool-cluster-manager
SME: @ filonenko-mikhail

Details

A follow-up on #3897.

Total: 13

High priority (13 sp):

• [TCM] What's new in 1.2 #4411
• [TCM] Managing Tarantool users #4317
• [TCM] Failover and switchover #4250
• [TCM] Migrations #4349
• [TCM] LDAP #3635

Note: tasks with medium and low priority are moved to #4553