Add override option

[sebasrp]

Is your feature request related to a problem? Please describe.
I want to have the ability to override default Service Limits (for accounts with increased limits).

Describe the solution you'd like
The override should be done through a file I create that specifies the different overrides I want (account, region, service, quota)

Describe alternatives you've considered
None - sometimes what is displayed in service quotas and/or the service's API is not synced with the manual update they have created in our account

Additional context
NA

[sebasrp]

Support in Service Checker. 0db6e2d

remains adding it into awslimichecker and the cli itself (support to override through cli argument and/or json file)

[sebasrp]

desired json format for input of quota overrides:

{
    "kinesis": {
        "Shards per Region": 123,
        "On-demand Data Streams per account": 456
    }
}

[sebasrp]

added support for json input in CLI: 00606a5

[sebasrp]

Last remaining thing: add support for cli argument to add this manually (not through json).