fix: allow configuring max_stream_count

[de-sh]

Closes #

Changes

Streams limit is made configurable
NOTE: Pre-allocates size of stream map

Why?

Trials Performed

1. Ran uplink as usual with a max_stream_count unconfigured with 21 streams(including system stats streams), failed to accept 21st stream with:

�[31mFailed to create "t12" stream. More than max 20 streams�[0m

2. Ran uplink with max_stream_count configured to 40 with upto 30 data streams, no issues observed
3. Ran uplink with max_stream_count configured to 40 with upto 41 data streams:

�[31mFailed to create "t42" stream. More than max 40 streams�[0m