API to manage replay host instances on AWS

Need HTTP API to start or terminate AWS replay hosts. Data should be held by webservice. 
 

```[tasklist]
### Tasks
- [ ] https://github.com/eosnetworkfoundation/replay-test/issues/77
- [ ] https://github.com/eosnetworkfoundation/replay-test/issues/78
- [ ] https://github.com/eosnetworkfoundation/replay-test/issues/79
```
