Support migrating arbitrary time ranges of data

Right now the `influxd migrate` tool only supports migrating entire shards of 1.x data into a 2.x OSS instance.

The PR for the tool is here: https://github.com/influxdata/influxdb/pull/17016

We should support arbitrary time ranges of data, so that a user can decide how much data they want to migrate from 1.x to 2.x.

I have already done the work to add the flags to support this: `--from` and `--to`. Those flags will expect the user to provide `RFC3339Nano` formatted timestamps. Currently those flags will cause an error if used, so that needs to be rectified.

Secondly, the `processTSMFile` method will need to be implemented. Unlike the `processTSMFileFast` method the `processTSMFile` needs to look at the time range of blocks within each TSM file, and compare that to the `from` and `to` flag values.

If a block is completely overlapped by the desired time range then it can be completely migrated over. However if a block is only partially covered then it will need to be decoded, chopped up appropriately, and then encoded again before migration. If a block is not overlapped at all it should be excluded from the migration.

It is important that index entries for blocks excluded from the migration are omitted from the 2.x file, and that index entries for partially overlapped blocks are updated appropriately (e.g., updating the `start` and `end` times).

#### Definition of Done

- [ ] `from` and `to` flags don't return an error;
- [ ] `processTSMFile` implemented;
- [ ] Test cases for `processTSMFile` (hint - consider accepting an interface that can write and seek, and then using buffers in tests to write into).
- [ ] ensure `from` and `to` flag documentation is clear. Right now it doesn't mention the format the flag values need to be in for example.

Start by reviewing the referenced PR and the `influxd migrate` entry point, then compare the existing `processTSMFileFast` method with the required `processTSMFile` behavior. Add coverage for `processTSMFile`, verify the `from` and `to` flags accept RFC3339Nano values, and ensure their documentation states the required format.

Written by the indexing model from the issue text.