Handle Full Text Search phrases outside of individual segments.

[NotJoeMartinez]

The method of returning keywords doesn't work well when the users searches for a phrase that exists across separate rows within the transcript. It also doesn't provide much context. For example if the query is foo bar pancake yeet and the rows are ['foo bar ', 'pancake', 'yeet'] the current method will return three rows and offer little context. If we create a dedicated table for the full transcript and combine it with the fts5 snippet function we can allow the user to control the number of words around their search keyword and still provide precise time stamps. We still need a way to find the time stamps of the returned snippet given a segment of arbitrary length.

[NotJoeMartinez]

Proposed solution to finding time stamps from snippet referenced in #178

def find_phrase_indexes(phrase, arr):
    marks = []
    fullText = []
    for i, row in enumerate(arr):
        for word in row[2].strip().split():
            marks.append(i)
            fullText.append(word)

    ans = []
    curr = 0
    phraseArr = phrase.split()
    for i, search in enumerate(fullText):
        if search == phraseArr[curr]:
            curr += 1
            if curr == len(phraseArr):
                ans.append([marks[i-len(phraseArr)+1], marks[i]])
                curr = 0
    return ans