Reduce pmt/ddci memory footprint and add ability to track it

[catalinii]

• changed pmt->pmt from a static array of 1500 bytes to dynamically sized array at the end of the struct (new pmt size will be sizeof(pmt)+pmt_len
• changed pmt->ca and pmt->stream_pids from having static desc and private_data to dynamically sized arrays. Also now they hold pointer to struct instead of fixed size array to reduce memory consumption.
• fix the accessing pmt->ca + pmt->stream_pid in all code using it
• allocate a pmt in process_pmt instead of process_pat when we know the size of the pmt_len.
• change active_pmt logic to account for this use case
• refactor alloc1 into _alloc, realloc1 into _realloc, free1 into _free
• track memory usage using a hash_table where the key is the pointer and change key size to 64 bit
• create ensure_allocation which dynamically the size of an allocated pointer based on new size in batches (basically allocate memory every 8 elements to prevent allocation for each element).
• export the hash table to the web page
• calculate statistics in the web page (how many allocations and their sizes)

Most of the relevant changes are in pmt.c.

[Jalle19]

Any chance you could split these changes into smaller commits?

[catalinii]

Updated description. Is going to be really painful to split this into smaller parts, but I added description to the changes. Hope it helps. If it is does not, I will try to split it.